I don't think she's generic, actually. She has a certain Selma Blair-ness about her. That sort of flat intonation that sometimes works and other times...just feels flat.
I can't really think of a thing she's done that hasn't been just exactly like that. Even when it worked, more or less, it was still mildly baffling--I thought she was more or less okay in Legally Blonde, but there also wasn't anything remotely remarkable about her performance. I couldn't see any reason why the casting director had gone with her instead of, say, twenty other people just as pretty and polished and vaguely East-Coast-classy-looking but more animated, more interesting, more something.
I file her mentally somewhere in Keanu territory, only a bit lower down because whatever his faults with the spoken word, he has incredible physical presence and the people who've worked with him are totally endearing in their inability to shut up about how generous and engaged and egoless and considerate he is to work with, but she seems to be a presenceless cipher.
I got a huge amount of enjoyment out of the first Hellboy by mentally blunking her out and replacing her with Aly Hannigan (one of the best performances Hannigan has never had the chance to give); sounds like I may have to do the same with the sequel.
eta: She had a brief cameo in a late episode of Friends, IIRC. Matthew Perry seemed to rouse her to something close to sparkiness; it's the most lively anything I've ever seen her do, so much so that I forgot until just now that it was her.