I had ultimate installed on a test machine and liked it, so bought Home Premium 64bit for my own PC. It runs great and I prefer it tons better than XP.
I have a C2D, 2GB ram, 320GB partitioned SATAII HD.
It looks great on my 1920 x 1200 screen

not to mention they've paid much more attention to the usability side of things. Oh, and it's more secure (well at the moment anyway).