Have you read Kelly Armstrong? I have to say, as both a sci-fi geek & a Bridget Jones person, I loved Dime Store Magic - silly as it sounds, it's normal neurotic 25 yr old with witch powers, a lingerie obsession, the knowledge that she's a little too plump, & the continuing mental note that if she's going to keep getting into these situations, she really has to actually start going to the Spinning classes she keeps thinking about trying.

Oh, and there's a slightly dorky thinky boy who she really shouldn't be seeing but just won't go away...