I recently got the game on sale and I've been trying to put together a melee-focused Cleric build. Here's what I currently plan on (although I realize I probably won't even get close to 40):

Race: Human

Alignment: Neutral Good

Class: 21 Cleric / 12 Fighter / 7 Weapon Master (5 Cleric > 1 Fighter > 4 Cleric > 3 Fighter> 7 Weapon Master > 6 Fighter > 3 Cleric > 2 Fighter > 9 Cleric)

Starting Abilities (Base Abilities at 40):
STR: 15 (27)
DEX: 13 (13)
CON: 10 (10)
WIS: 15 (19)
INT: 13 (13)
CHA: 10 (10)

Skills (without modifiers):
Persuade: 22
Concentration: 25
Discipline: 34
Intimidate: 4
Spellcraft: 43
Tumble: 20

Feats:
Power Attack
Cleave (Human Bonus)
Dodge
Weapon Focus: Warhammer (Fighter Bonus)
Mobility
Expertise
Spring Attack (Fighter Bonus)
Whirlwind Attack
Weapon Specialization: Warhammer (Fighter Bonus)
Improved Critical: Warhammer
Great Cleave
Great Strength I
Epic Weapon Focus: Warhammer (Fighter Bonus)
Great Strength II
Epic Weapon Specialization: Warhammer (Fighter Bonus)
Overwhelming Critical: Warhammer (Fighter Bonus)
Great Strength III
Great Strength IV
Devastating Critical: Warhammer (Fighter Bonus)
Great Wisdom I
Maximize Spell
Great Strength V

Domains: Good, Healing

I would appreciate any advice, thanks.

Edit: changed the build to Warhammer/Shield instead of Greatsword, added skills and a few other tweaks.

First off, just a note on the campaigns:

- the original campaign will take your character to around level 16 or 17.

- the first expansion (SoU) is intended for a brand new level 1 character. While you can take your OC character into it, the game does not scale to your level, so it would be a complete cakewalk and quite boring. A new character will reach level 12 or 13 by the end.

- the second expansion (HotU) is written as a sequel to SoU, although you don't have to play it that way, as it's only referenced in dialog a couple times with the assumption that your character is the hero from SoU. HotU is intended to be started by a level 12 to 15 character. If your character has less than 12 levels, the game will grant you enough XP to start at level 15. If your character has more levels, nothing is taken away. By the end of HotU, your character will reach level 27 or 28.

Having pointed this out (apologies if you're already aware of this), a few comments on your build:

1) are you determined to go with Weapon Master? It's a huge feat investment for not really a lot of gain, especially if you're not going to choose a weapon with a high base critical range (such as a Kukri). I'd suggest looking at just a FTR/CLC instead.
2) If you're not opposed to this for roleplay reasons, I'd suggest starting with a lower CHA and adding those points to STR. If you decide to dump WM, then also lower DEX to 12 or 10 and either raise INT to 14 for more skill points or lower it to 10 and use the points in WIS, STR, and/or CON.
3) For domains, dump Sun. You're a melee Cleric, not a Turning machine, so just accept that you're going to beat the unliving hell out of them. Good is a nice choice because of the Stoneskin spell, but a better choice to get the same spell at the same level is Magic. You also get Mage Armor (will add at least +1 to your AC from the Dodge AC boost) and a couple nice offensive spells as well (Melf's and Ice Storm). Another good choice that includes Stoneskin is Strength domain. This also gives you Divine Power as a level 3 spell (and you still get it as a level 4 spell as well) and this is a damned useful spell for a melee Cleric.

Another domain to consider is Trickery. The invisibility spell is always nice to have, but Improved Invisibility is bloody awesome. Combine that with Stoneskin and you're rocking. I'd personally go with Trickery and Strength.

The only other consideration is the Travel domain, which provides Haste. But you can get that from potions and if memory serves, there are boots of speed as well.

So, yeah. I'd go with something like this:

4 FTR and 16 Cleric levels by level 20. Add a couple more FTR in epic levels for an extra feat and to get Epic Weapon Specialization. Domains of Trickery and Strength. I'd set him up like this:

STR 16 <---- Boost this all the way, except as noted below
DEX 8
CON 14
INT 10
WIS 16 <---- Boost this only when needed in order to be able to cast the next spell level(s)
CHA 8

You'll get 3 skill points per level. Dump them into cross classing Tumble (for an AC boost for every 5 ranks bought), and maybe Spellcraft and Discipline* or Listen. Rally, there aren't many must-haves for skills in the OC if you're playing a Cleric.

*You could save skill points to dump into this when you take FTR levels, so you don't have to pay 2-for-1.

You could even consider dropping INT to 8. You'll still get 2 skill points per level, which is plenty for this character. You can boost DEX to 10 that way.

NOTES:

- low DEX may look concerning, but you'll be wearing plate armor and can boost it to the maximum DEX bonus plate allows via Cat's Grace potions or items that give a DEX boost.

- since you only get a stat boost every 4 levels, pay close attention to when you'll be gaining level 7, 8, and 9 Cleric spells and make sure you boost your WIS score at the right time. You don't want to leave yourself without the ability to cast some higher level spells because you didn't plan your WIS boosts at the right times.

Hope that helps. Of course if you're more of a pure roleplaying mind, much of this advice is powergaming, so you may not want to bother with it. Still, it's food for thought anyway.

My build is mostly oriented towards powergaming, but it does account for some roleplaying (see 3). Thanks for the info on the expansions, I still wasn't sure about them (also, what about the premium modules?).

1. Yes, mostly for increased multiplier and ki critical. I chose the Greatsword because it is the most damaging 2-handed weapon with the highest potential threat range (13-20 with ki crit, keen and imp crit).
2. I'd prefer not to have any negative modifiers.
3. I wanted to pick domains that would be associated with my deity (Pelor), not just what would be the most powerful.

I'm still not sure how I'm going to allocate all my skills (aside from the mandatory 4 points in Intimidate). I'm on the fence about Tumble since while the AC bonus would be nice, it is a cross-class skill and I wouldn't receive attacks of opportunity for moving with Spring Attack. As I understand it, some skills are worthless (or very situational) such as Parry or Ride.

I've been very meticulous with this build (made a spreadsheet for it) so I accounted for things like when to boost my WIS so I can cast the appropriate level spells. Thanks for the advice.

The Premium modules are also designed for new level 1 characters. I believe the only one that may scale is Kingmaker. I can't recall for certain on that one though. The Greatsword's crit range is 19-20. Ki Critical adds 2, which brings it down to 17-20. Improved Critical doubles the crit range, but that applies only to the original range, which is 2 (19-20). This means it drops to 15-20. No worries. I suspected as such when looking at the original point spread. Ah, okay.I'd still recommend dumping the Sun domain. Pick up Healing instead. You cast healing spells as if they're empowered (this even affects scrolls and potions), and you get the Heal spell as a level 5 spell. There really aren't that many useful skills in the campaigns for Clerics. I'd say maybe some Persuade (there are a few checks that can increase rewards, if memory serves). The Tumble AC boost would serve you well since your choice of weapon means you won't be using a shield.

Anyway, given your criteria, you look like you're pretty well set up with your original build.

If a premium module wants a higher level (I think a few of them start you at 3 or 7 or something), it'll dump massive XP on you just as you start the game. Then you can level yourself up. I can't remember which do that (and I may be thinking of community modules).

[scratch this]Also, do you need expertise for your build? It doesn't look like it would be useful at all. It won't work with a greatsword and you have low DEX. [/scratch]
You need expertise for the WM PC.

[scratch this]Also, I think you need 14 DEX to get mobility. I'll check that and edit if I find otherwise.[/scratch this]

You need 13 DEX for mobility. You're good.

I have nothing worth saying without scratching. :D

I understand that, but if it were also keen it would be 13-20.

Also I think I will dump Sun for Healing, thanks.

Gah! You're right. My bad. Apologies.

There are several good modules on the vault for post HotU gaming, like this.

Haven't played that myself as I'm not into high level powergaming, liking low level, low magic adventures better.

The Island I actually played, and it was a neat romp,
albeit it's only a few hours long and has an item strip in the beginning.