I try something similar with my desktop. There's some games I like which just don't seem to work well on Wine, and I'm guessing they won't be great in a VM. On the other hand, for day to day stuff like surfing the web, file management, photo processing, listening to music etc I find Kubuntu much nicer to use than Win7.

My current approach is to have Win7 as the base O/S, but with Kubuntu running in a VM. I have the VM maximised, and the status bar turned off so it fills up the screen. At the same time I've set the Windows dock thing to autohide. Most the content, like music and photos, live on the host, but are accessed via shared folders in the VM. The first thing I do after logging in to windows is to fire up the VM. I then play my games on Windows, but have Kubuntu running in the background to do most the stuff I need.

It's not perfect - it uses up a fair amount of RAM, and window switching can get annoying if I'm switching a lot between a game and something else like a web browser in the VM. On the other hand, it means I can do the things I want in Linux, and play the games in Windows, without needing to constantly reboot into a different partition.

In an ideal world I'd have it the other way around, with Windows in the VM, but I don't trust yet that a lot of my games would work well.