My current system hasn't gotten any upgrades, aside from more storage, in nearly 15 months. Its an E8500, 8GB DDR2, Radeon 4870 system.
I'm not planning any significant upgrades until Sandy Bridge and Bulldozer are fully established across all market segments. However, I may opt to drop in a Radeon 6970 in a few months. Might. My 4870 is getting a little long in the tooth. Still runs everything very well, but I'd like to dial up the settings somewhat.
When I do a full rebuild, I'll probably keep my current full tower ATX Lian Li case because its Fing awesome and it'd keep the build cost down. But, I'd like to build something much smaller, such as a mini-ITX system. Something with a smaller foot print that still allows me to play most of my games are decent quality settings. I can pick up a Drobo or something similar for storage.