I just finished the OC and now I started to play MotB.
I used a char very similar to this:
http://nwn2db.com/build/?67066

Pros: -damage is OK, not extremely high but good enough
- you don´t have to run around during battle.

Cons: - It looks stupid when you fight with a bow while you are surrounded by enemies. There is no aggro system so you cannot sent them to your tank.

-but the most importand reason why I stopped playing after 1h MotB: You need tons of ammo
late in the game. You have: 6 base attacs per round + rapid shot + haste (+ manyshot if this uses extra ammo)

When you come to town in MotB you can get 99 arrows+4 for over 2000g (maybe even more, I don´t remember the correct number and it depends on your appraise skill which is usually not very importand). Those are being used after a bit more than 1 minute of battle. Though you have no problem getting lots of money in MotB, a char that burns 2000g per minute is not effective, no matter how many damage you do.

In the OC I used a longbow+3 with infinife ice arrows. But you loose your weapon when you import your char to MotB. Unless you tell me that I can find a good bow with infinife ammo in MotB fast, I start again with a new char.

Never played an archer in MotB, so I can't speak for weapon availability in that campaign.

In general, consumables in the D&D RPG's are heavily overpriced. The cost of things like potions or magic arrows was based on the table-top game. In the conversion from tabletop to computer, the experience gain rate and loot per battle were substantially decreased to compensate for the fact that you could fight many more battles much more quickly than in pen and paper. However, the cost of consumables was not decreased accordingly, so as a result any character who uses consumables regularly is going to be paying a significantly larger chunk of their total wealth.

Until now I was happy about the high prizes for magic or elemental ammo.
I used normal ammo and sold the stuff.
At the middle of Baldurs gate 2, all my chars had a ranged weapon with infinite ammo.

But at the beginning of MotB, you have a high level char (=many attacs per round), no special weapon and there is no shop that sells normal ammo.

Yeah, this is an issue with archers in both NWN1 and NWN2. Archers are basically hosed when it comes to ammo as:

A) they often can't carry enough to last any appreciable amount of time after they gain a significant number of levels and have several attacks per round.

B) the ammo prices, considering how much they go through, are completely prohibitive.

The few times I played archers I generally swallowed my pride and bought as many as I could afford and then used the console to give myself more. IMO, It's completely ridiculous that a melee character only needs to shell out a certain amount of gold once and then can make an infinite number of attacks from that point on while an archer needs to basically take out second and third mortgages on their homes just to attempt to keep flush with ammo.

Thats the reason why I mostly play melee chars in RPGs.
All you need is a good weapon and armor and then you can fight forever.

An archer needs tons of ammo and you have real problems when its finished and there is no shop nearby (like in the middle of a dungeon where you have to fight your way out)
In baldurs gate 1 half of the inventory of each char was filled with arrows or bullits. But there you could buy cheap standart ammo at every shop.
This is not only in DnD games. Somebody wrote in arcanum that he was very happy with his gunfighter until he found out he wasted all of his money for ammo just to clean the sewers from rats.

I also use rarely casters as main char in DnD games. At high levels they are very powerful. But when you have used your spells and you cannot rest, you are useless. Mostly that is not a problem in NWN, but there might be a place where you have one hard battle and then you have to win another battle before you come to an area where you can rest. (This did not happen to me until now but murphies law says: It will happen when I do expect it and I will save the game after I used all my spells for the first battle) The final dungeon of the NWN2 OC may be a good example. There are lots of enemies and when you rest there is a high chance more enemies spawn.

edit: I dicided to play MotB with a fresh monk/cleric/sacred fist. When I start the game I have a char with many attacs, good AC, buffs and no need for any weapon. I think thats a good way to heal myself from the archer shock.

I beat SoZ as an Ranger specialized in archery. It was mad fun but yeah... lotta challenges. Never could have done it without a really powerful magical chain shirt for when I got mobbed. This didn't happen to me quite as much as it seems to have happened to you. This is one situation where henchies' natural tendency to charge out in front of the party and attract every monster in the area can be put to good use, just make sure they are well potted, keep your spellcasters under tight control, and don't be stingy with your magic when they get mobbed.

Ammo cost would be more balanced, if you coud retrieve arrows, bolts, etc. from corpses, as in real combat. There should be a basic rate at which ammo could be retrieved (let's say 80%) and overall rate should depend on the quality of ammo, archer's level (some feats, maybe?) and type of creature slain (no retrieval from fire elementals and such, low rate from constructs or heavily armored enemies).

General problem with ranged weapons in cRPGs is that they should be extremely overpowered, if they would act as real ones ("one shot - one kill" or "arrow hail" tactics), so they're dumbed down to balance them with melee weapons.

/edit: missing letter/

Any weapon can one hit-one kill. D&D has very deliberately eschewed this mechanic as counterproductive to the type of epic storytelling it represents. That's just a no-go. All weapons are nerfed for this purpose, not just arrows.

Arrow hail is actually implemented in the D&D mass combat system (at least it was back before WotC screwed everything up and dropped mass combat entirely), it's just not used in the heroic melee. Check out Chainmail for more info on D&D mass combat (also Battle System).

I'm not sure trying to balance the system with realism is a good idea. While it would be easy enough to assume that hits are recoverable and add them to a monsters inventory it would be nerfed by applying real world load-out limits. In the real world archers rarely carried more than a dozen arrows and never more than a score.

Think of your arrow load-outs as "firepower ratings" representing lost, broken, and worn out arrows rather than an actual arrow count.