I bought a new iMac last week (the 21.5" since the 27" is just a bit too over the top for my taste 
) to replace my aging MacBook. Performance of the machine is very nice and in general it's just a great system. The screen is fantastic as well and i'm definitely loving the resolution (1920*1080). The new Magic Mouse is excellent, though i do miss the middle-click (which i used to use extensively to open links on sites in new tabs).
But the best part of it is that i also upgraded to the newly released VMWare Fusion 3. As some of you already know, i use my Mac for all regular computer usage, and i use a virtual machine to run Windows which i only use when i'm doing .NET development at home. I was still using a virtualized Windows XP on my MacBook because for one, i can't stand Vista and i figured it would be way too slow to run in a virtual machine on the MacBook anyway. But for the past 2 months or so, i've been using Windows 7 at work and much to my surprise, i'm actually very happy with it. It's still butt-ugly, but at least it runs nicely, it's fast, it's stable, and it hardly ever annoys me. It's like Windows 2000 all over again :p. So i figured it was time to make the switch at home as well. So now i have a virtual Windows 7 with Visual Studio 2008 running on the iMac (only when i wanna do .NET stuff obviously) and it's running very well. Performance is really unbelievable, considering that it's virtualized and i only gave the VM 2GB of RAM. I did disable Aero (i could use it, but the difference was noticeable) but i kept the typical new Windows look, if only because the classic look is even worse.
While writing code at home had become more of a chore than a joy because of the slowness of running a virtual Windows XP on the MacBook, it's now really enjoyable again 