Using Core books only:

Sorcerer (Cannon) = Cannon + Heartbeat. You walk around and blast things from a long way away... (you could be the dude who could create an entire illusionary world around other beings 24/7 if you want...)

Sorcerer (Squirrel-Puncher) = Everybody gets neutered. Hold Person, Enfeeblement, Grease... if it is an enchantment/necromancy and likely to make someone else's life harder... that's your kind of spell.

Wizard (ALL KINDS) = "I believe I have Rary's Rather Large Rat Repellant Emanating Fog of Lavender in my scrollcase here somewhere... oh there it is right next to Mordenkainen's Magnificent Cutlery Set" Seriously, if its on a scroll buy it and write in your book, then copy it out of the book onto a Scroll and have a scroll case that was single-handedly responsible for the Deforestation of the Great Desert... Most people seem to forget about Downtime and Scribe Scroll... Wizards should NEVER run out of spells, if you run out then the next time you go to town... BUY LOTS MORE PAPER YOU TWIT!!!!

Cleric = I am the impenetrable walking fortresss of smackdown. Spells + Heavy Armour... even just using the Core Books... seriously well-done Clerics are HARDCORE. This is before you include the overpowered cheese that allow you to burn turning attempts to power metamagic feats... (Which peanut brained crack smoking chimpanzee thought that was a balanced mechanic????)

My personal choice: Wizard. But then I have played Wizards and Rogues for almost every single one of my characters... the party got the poos with my Saintly Paladin and another time my Cleric basically died when the rest of the party was nerfed at the same time (but there was comedy GOLD leading up to that point, including the Cleric impersonating the god of Kuotoans)