I’ve been listening to a variety of mellow 45s on the excellent Office Naps vinyl blog, which features a nice collection of 45s uploaded for your listening pleasure. The genres on Office Naps include exotica/space age bachelor pad music, psych, post-punk and new wave, and many more.
Office Naps has been running since 2006 and there is an appropriately massive collection of 45s to listen to. These are obscure enough to make the rabid vinyl-phile collector happy and the music is top-notch regardless of genre. I have to say, this is my current favorite. Office Naps is a great way to spend an afternoon.