i don't really believe in guilty pleasures... i feel like you shouldn't be ashamed of what you enjoy. that said, there are quite a few things that i love that are pretty unhip to enjoy considering my general taste in obscure post-punk/shoegaze/etc.
lana del rey
tori amos (mostly up to and including choirgirl, though the new record is surprisingly great)
mechanical animals
the outfield- your love
the carpenters (yesterday once more KILLS me)
tom petty & the heartbreakers
the first two oasis records
the cranberries (especially the first record, which is perfect)
asia- the heat of the moment
sponge- plowed/cracker- low/local h- bound to the floor
alan parson's project- eye in the sky
toto- africa/it's a feeling
italo disco (not unhip in my circle really, but it's really, really cheesy a lot of the time)
u2 (up to and including pop, but especially the 80s run. they get a lot of unnecessary shit for being such a solid band for a while there)
hole- live through this and related tracks only
freestyle (debbie deb, noel, the cover girls, shannon, pretty poison and all that other miami-tinged synthpop)
PUMP UP THE JAM (technotronic)
...and apparently it's not cool to like bruce springsteen either, but darkness on the edge of town & nebraska rank pretty highly.