Hmm, Mrs P's music taste seems remarkably similar to mine (down to the old Goldfrapp but not new Goldfrapp).
To answer the original question, I find new music on radio (R&M, Radio 1 in the evenings), Spotify 'related artists' page, Metacritic.com (website that combines loads of album reviews into one score), and recommendations from friends.
My suggestions for new bands (not that they're really needed at the moment!) would be Band of Horses, The Shins, Band of Skulls, Guided by Voices, Built to Spill, Broken Bells, and Sparklehorse. Also if the Flaming Lips album you've heard wasn't Soft Bulletin then you should probably check that out, one of the best albums ever IMHO.
Now I'm off to find out about the Explosions In The Sky and Modest Mouse albums mentioned in this thread, as I hadn't heard about them before:)
Edit: just remembered that Glasvegas aren't on the list of bands I recommended, and should be!