Just used Amazon MP3 for the first time and I have to say i'm well impressed, finally found a simple MP3 download site that does what i want it to do.
The download software takes literally seconds to install and then you just buy the songs how you normally buy CD's. The biggest and most important things for me are that they are downloaded in 256kbps and are DRM free. I've used a couple of other sites in the past (although not recently) and have gone to put them on MP3 CD's only to find they don't play on other devices which totally defeats the object for me as i don't really use a personal mp3 player.
I'm the sort of person who will always buy an album on CD if I want the whole album but 70p odd for a single (and the 4 I just got were only 29p each!) that I can play anywhere i like is well worth having!