[Nerull]

If it is your first time playing the game, go with a mage. Until you know the spell system, you could end up making a spell choice with a sorcerer that could come back to haunt you. However, there are plenty of spell lists for sorcerers out there (just search for them and you'll find them). The only bad part about a mage is that you could not memorize something that you find out later you need. Always a risk, especially your first time through without walkthroughs. That's why it's a good idea to have 2 mages and 2 clerics your first time through (to give extra casting slots to the party, so you can "spread out" a little bit). Also, keeping scrolls of those "lesser used" spells is a lifesaver. Always buy scroll cases when you find them.

However, once you know the spell system, and realize that you can use scrolls, wands, etc., the sorcerer rules. You really don't use that many spells out of each spell level on a regular basis. Thus, you choose the spells you know you'll use a lot, then just keep a scroll case or two with the spells you'll need on those rare occasions. You'll have extra castings of all of your main spells, and don't have to choose in advance how many castings of each you will need.

Best bet if you are using a party is to have one of each (one sorcerer, one wizard). The sorcerer knows the main spells used by the party, while the wizard is there to back up the sorcerer and to memorize spells that the party needs on occasion.