It doesn't really matter what class you pick.
If you work hard enough you can end up being all classes.
For example you pick warrior.
You then buy tailsman, you are now a warrior whom can use magic (sorc).
You then continue on to buy piety.
You can now pray (priest).
You then go further and buy scroll of alchemy and cauldren. You can now be an alchemist too.
Scroll of stealing is also buyable but kinda worthless, I have it and it's so hard to get itto work.
AndI don't know what special skills a barbarian have so I can't comment on them.