Questions of identity seem to loom large in Lifehouse's mind.

On their third album, they titled it after themselves, and now on its 2007 follow-up, they state Who We Are -- a declaration that could easily be a question depending on the punctuation and emphasis.

Does this fourth album add up to a statement or question? It's the former, but that doesn't necessarily provide a fulfilling answer for those doubters who can't tell Lifehouse apart from all the other polished post-grungers out there like, well, there aren't as many of them in 2007 as there were in 2000 when they released their debut, but the curious thing about Who We Are is that the trio still parties like we've just left Y2K.

This is utterly untouched by any new-millennium trend -- there's no garage punk, no emo, no spacy precious pop, no electronic flourishes -- it's post-alternative guitar rock preserved in amber, all shallow angst and earnestness, communicated through music that surges without hooks.

Since the band is starting to see the twilight of their twenties, this doesn't hit as hard as they used to -- despite guitarist/singer/songwriter Jason Wade's contention that he's battling inner demons by wresting angels on the opening "Disarray," it's hard to feel the toil and trouble here -- and they're starting to mellow, crossing over to soccer moms, either intentionally or not.

And they do it as they always have: with sincerity but little melody.

So, again, Lifehouse are pleasant enough, but hardly memorable, and hardly answering the question of who they are no matter how they try.

Indeed, they only leave the lingering question: why does a band that cribbed its name from Pete Townshend's legendarily complex rock opera -- so confounding to its creator that it sent him into a nervous breakdown before he abandoned it -- choose to sound just a little bit tougher than the latter-day Goo Goo Dolls?.