I develop on a MacBook Pro with a Apple Cinema Display hooked up to it. I've tried both VMWare Fusion and Bootcamp. When in Fusion, the only thing running is Visual Studio. I turn off everything - Aero, sound, etc. It runs fine for the most part. I use a dark color scheme and sometimes scrolling through code shows some lag. It isn't as pronounced now since I turned off Aero and what not, but does still show up every once and awhile.
I also use CodeRush and Refactor! Pro. It does a lot redrawing of the core Visual Studio environment (highlights, animated arrows, etc.). Most of them work. But I have noticed cases where they don't redraw properly when running under Fusion.
Now depending on the types of solutions you develop, you might not like Fusion. I do a mixture of desktop apps and web apps. The desktop apps work the same on the VM as they do in a non-VM install. The difficulty is that to get the performance I wanted, I turned off Aero, sound, etc. So your app isn't really what your clients are seeing. For web apps, it doesn't really matter.
The other thing I've notice is that sometimes WPF doesn't do an initial rendering under a VM. I have to resize the window just a smidge to get it to draw. Now this is only showing up in WinForm apps that display a WPF dialog. So maybe it is the WPF being hosted in a Winform under a VM that is causing it :)
Each thing taken alone is negligible to me. But add them all up, I just started using the Bootcamp partition exclusively. I get all the "prettiness" of Win7, my apps look like what my users will see, etc.
The biggest problem I have with Win7 is the apps just aren't as nice. I think Trillium is bloated compared to Adium. Pidgin works on Win7, but you can tell it's a GTK app. On Mac OS X, I used Gabble for Yammer. Windows doesn't have a native Yammer app except that stupid AIR app. And on principle I won't install Adobe AIR.
1Password is nicer than KeePass, Password Manager, or whatever Win password you use (if you use one).
iBank is nice (but not great) on the Mac considering I won't use Quicken and Microsoft Money has been discontinued.