Whats the Best Class Selection?

I honestly can't recommend a single class that's absolutely better or worse than any other. One possible reason for this is that I don't play at the extreme high end of the level scale (my characters generally top out around 100 total levels), though beyond that point I think the goals and question change.

What I've experienced is that the different classes simply have drastically different playing styles. Mages generally have to bone up on spells and be careful of melee combat until they reach mid/high level. Clerics can heal and I've found make pretty decent fighters if you want to play them conventionally; but the real power of clerics is in grouping and turn undead. These are both very different from the playing style of a straight up caster.

Warriors just beat stuff up, and do so very effectively. Thieves on the other hand are unusual; I like playing thieves, but they are the most unique of the classes. You can just beat stuff up if you want, but it's so much more effective to actually be a thief that I never bother to do so. I once leveled a thief to 30 doing nothing beyond thieving and occasional 'self defense' killing.

Most of the complaints I've seen about class disparity have been because the player didn't actually know how to play the class. If you try to play a thief like a caster, you're going to get your ass handed to you; yet somehow, this thought never seems to occur to some people.

Above total 100, the question becomes more 'what is the best class for getting huge amounts of exp' and 'what is the best class for getting fame'. For these questions, I think that some classes are in fact slightly better than others - but at 100 total, your lowest class should be around level 20, and it doesn't matter as much.