A Viable Solution - Multiple OS?

Hi All,

I have an Acer Laptop with XP installed. I also have a 9 year old kid who loves to go to all these kiddo sites and pay online games educational stuff etc, and a wife who surf's the net - both are not very net savvy and i end up with virus on my PC very often and need to re-format my pc atleast once in 3-4 months.

Now I have a Dell E520 with 500GB Space and Vista - to get over the above - but my issue is how I get over this infection thing? I tried using separate login's, firewalls, even restricting access on IE - but nothing works.

I was thinking of making 4 partitions - Since I have enough Space
1) Windows Vista - for myself.
2) Windows XP - Which my wife and daughter can use
3) Linux - for my project work and testing
4) Data - Like My documents etc

That way - I can create an image file for the 2nd Partition and everytime I feel - they are infected - just overwrite the partition - they dont loose anything as all data are stored in separate partitions.

I am sure many people out there with kids - having the same problem - Can someone give me a solution to this? Am I going up the right lane? or just plain making my life more miserable?????

Dev