Recently decided to purchase some RAM upgrades for my laptop. It's not that it wasn't that fast with 4GB, but when using a 2GB RAM windows 7 VM (VMware Fusion), things started to slow down. I still need to use windows in a VM for software applications like QuickBooks, and to access the KVM switch we have out in Buffalo. I purchased the upgrade from Other World Computing, aka macsales.com, where it was only about $130 for the upgrade. It was slightly higher than newegg, but OWC had the video card upgrade for my Mac Pro (A whole different fiasco). Anyways, the laptop is running lightning fast
Check out the article I just finished... It's a HOWTO on installing and configuring Windows 7 x64 in VMWare Fusion, which is VMWare's workstation product for Mac OS X.
I've had it running on my 8-Core Mac Pro for a little while now