Why not have it both ways? Both VMWare and Parallels allow you to use your Boot Camp Win7 install as a VM. That's what I do, and it works perfectly. If I need full horsepower in Windows, I reboot into Windows using Boot Camp. If I just need to go into Windows for something quickly and don't want to interrupt my Mac work, I use Parallels.
I've used both Parallels and VMWare Fusion, and prefer Parallels. With lots of memory and the SSD, routine tasks are seemingly just as fast in the VM as they were in a native Windows boot.
Just be sure you have enough space on your SSD for a decent Windows installation. I partitioned ~70 GB (I have a 512 GB SSD on my MBA) and am using about half of the partition for Windows 7 and Office 2010 combined.