I do not know if this has been posted before, but there is a trick to unlocking every skill at the character create screen. This works for both versions of the game. First you want to add 10 points to say like climbing, then add one point to it and then take away 10 and you will have one point left in that skill. You can do that with everything skill and have at least every skill at 1 at the beginning and just grind them out. This is how I always play,.

Yeah, but that does break the game for some classes, as the game in some of the sequels will think you're another class and if you don't have the items you should as that class, or enough skill, you'll be stuck. (and you won't be able to use your own class-specific option)
Anyone who wants to do this and plans on playing the later games (or starts out in them) should also google this first or look for it in this sub-forum because having all skills as one class (I think it was thief in particular, or mage with thieving skills) will make it unable to attend W.I.T. exam in QfG2 or something equally important and when switching classes will break something in some of the games if you have certain skills I think (fighter/paladin stuff?).

However otherwise it's fun to try an all-skills playthrough, but you don't need to cheat, all you have to do is pick the thief in QfG1 (maybe the mage too? try and see which allow it) and put points into the skills you don't have trained at all. And in the sequels you usually can max out all of them - however the question is, besides wanting to have a jack-of-all-trades, why not just play with each class instead of mixing it? This way you'll miss out on some conversations and you might not obtain some things you should if you do it another class' way.

I use the fighter for this and I have had no problem at all with all five games. I always max points and everything. I haven't had it break for me yet on my ten or so playthroughs.

That's why I mentioned specifically it broke or might break something for the thief with mage skills or mage with thieving skills.

It should never outright break anything. You might end up with different point-score totals, but those don't have any impact on gameplay. The only 'hard' consequences of cross-class skills are:

1) Your character's class may change when you transition from QFG2->QFG3 based on the character's skills and what they did in QFG2, most notably whether they completed WIT (which requires the magic skill), whether they qualified to become a paladin (not directly skill-dependent), and how they approached the end game sequence (which may be skill-dependent based on the path taken).

This is actually a 'soft' consequence because QFG3 will prompt you to choose which class the character should be imported as, so you aren't actually stuck with QFG2's determination.

2) In QFG5, the game will consider your character to be a Thief in addition to his actual class for the purpose of marriage if he has the lock picking skill, and that can take certain options off the table.

The only one that can have significant reprocussions is the pick locks skill in QFG5. This precludes marriage with Katrina and Erana, and also causes many thief-specific subquests to become active which can be problematic if you arrest the guy who outfits you with the necessary equipment to complete those quests!

Oh yeah, those were the ones I was thinking of! :) Also, wasn't there something with the WIT or that's just me remembering that you could do WIT as a thief or something like that?

You forget the ending scene in QfG2 as a fighter with magic (or at least with reversal). Instead of getting the fighter ending scene, you'll get the magic user one.

IIRC, the ending scene determined by your method of entry into the palace. If you cast the open spell to open the gates then you get the magic user ending, if you bash them down you get the fighter ending, and if you scale the walls you get the thief ending.

Bash doors open, fight Khaveen, open doors, get zapped, break doors. I don't recall being able to do the proper fighter ending at that point, since Ad Avis would always try to turn me into my true self, instead of creating a ring of fire. I will have to test it again though, assuming I have a save near there.

JMich is correct. What happens in the ritual chamber (assuming you broke into the palace through the front door, and not through the harem) depends on whether you have the Reversal spell or not.

If you don't have Reversal, then you will automatically go into combat with the gargoyle and have to run away from it, and when you break the spell Ad Avis will cast Flame Darts on you, and you have to run up to him before he finishes, running straight through the brazier when it bursts into a wall of flame.

If you do have Reversal, then the gargoyle will knock you down, and the 6:00 candle will be lit before you get back up. When you break the spell, Ad Avis will cast a spell on you from which only the Reversal spell can protect you, and then you need to knock the brazier onto his feet.

If you broke in through the harem, then the above is irrelevant.

Found out you don't have to break the spell at all. Just escape, move to the other side of the room, and tip the brazier. Ad Avis dies, and without someone to complete the ritual, you win.

With the Reversal spell, you have to "fight" the statue, then escape, and then you can move and tip the brazier.

Do you get to chose if you want to be a paladin at the end of QFG2? Or do I have to screw it up on purpose if I don't want to become one?

When importing your character in the later games, you can change your class, no matter what your class was saved as.

If you want to avoid being a Paladin, just act like an immature gung-ho fighter. Kill the Griffon in combat, "kill" your opponent in the EOF initiation, put on the x-ray glasses while the Zayishah is changing. I think any one of those three in particular are complete disqualifiers. If that kind of behavior doesn't appeal to you, I don't see why you wouldn't want to be a Paladin since it's basically just a Fighter with special abilities and more story options.