I upgraded mine in November and it was a bit of a pain. Personally I ignore the PC market for years at a time until I need to upgrade and then do an intensive crash course on current technologies so that I can make an informed decision. Some people keep up to date all the time but I don't have the will power to stop myself buying stuff I don't need if I look into it too much! 
Still there is a nice feeling of satisfaction when you have a nice new machine with everything running smoothly having put it together yourself 
I last upgraded in November too, and went for the safe Intel i5/AMD 6850 option. I tend to upgrade every 2 years though wish I had waited now.
Seen the Asus 3D monitor, 120hz of goodness. I would couple it with an Nvidia 560Ti and a 120Gb SSD. Maybe I can sneak the odd purchase past the better half before the summer holidays zap the bank balance.
As for Steam, I can't complain when the odd sale throws up a £1.74 gem. But mainly I rely on Amazon. From under £3 to £5, there's quite a few original bargain PC games to be had there, with low or no postage its good for the collector.