Assuming out-and-out bullies (Vicky from Fairly OddParents, Shelly from South Park, etc.) don't count, my choice from the above was Montana Max---at least Angelica (and almost all the others) have a *trait* of redeemability to them, but not Monty....
And still feel Bart is way worse than Lisa, who's well-intentioned but can sometimes be a bit shrill, not to mention the futility of trying to improve life in a sitcom setting where by sitcom definition aboslutely nothing can change (or it'd "ruin the show"); the fact the Springfieldians are complete idiots, of course, makes Lisa's efforts all the more futile. Granted, this opinion's based on the 90's-era Simpsons episodes; have no idea what they're doing to Lisa and Bart nowadays...
-B.