Besides the differences in the way they cast, you should consider the following differences:
A wizard will always have a high intelligence, which means that they will have lots of skill points even though the class only grants 2+int mod per level. A sorcerer's high charisma will make them "social", but there are no extra bonuses for high charisma. In fact, its possible for the wizard to surpass the socialness of the sorcerer by buying ranks in diplomacy, intimidation, and other charisma based skills. Personally, I really like the idea of giving a sorcerer 4+int skill points per level, as Monte Cook did in his revised version. I was quite disappointed this change didn't make 3.5.
Over the course of leveling, a wizard gets 4 bonus magic feats and Scribe Scroll for free. The sorcerer gets none of this. A good rule variant (also from Monte's alternate sorcerer) is to give a sorcerer Eschew Materials for free at first level. Again, I was dissapointed to find this change didn't make 3.5.
The sorcerer gets proficiency in all simple weapons, where the wizard only gets a select few.
A sorcerer cannot use Quicken Spell without also taking Arcane Preparation.
Hope this helps.