Ok, you asked for it (trying to go mainstream-ish here):
Penelope (better than it should be - I enjoyed it)
13 Going on 30 (Jennifer Garner is cute and hey, Mark Ruffalo!)
Baby Boom (Diane Keaton!)
Romancing the Stone (not sure if this counts as a rom com, but anyway, it's awesome)
Never Been Kissed (haven't seen it in years, but I remember enjoying it in a my-expectations-are-not-very-high kind of way)
That Touch of Mink (ok, it's older but it's very accessible and very fun)
The Importance of Being Earnest (the old one is way better, but there's a new that's ok, too)
Green Card (well, it's classic, in spite of Andie MacDowell, the non-actress)
Overboard (Goldie Hawn is cute like Meg Ryan! and hey, Kurt Russell!)
Also, I didn't really like The Holiday, but some people do - and Kate Winslet is in it so that's something. Your roommate might like it.