Memory upgrade thoughts

[Jargy]

I'm currently running 32-bit Vista on a Q9550 with 2x 1Gb OCZ DDR2 8500 memory. I'm in the process of doing a few upgrades, which will include going to W7 64-bit.

I know 64-bit will allow me to use more than the 3Gb that a 32-bit system will, but is 64-bit more memory demanding?
Is it worth just adding 2 more 1Gb sticks (so 4x 1Gb), or am I much better off just buying 2x 2Gb sticks and selling off my 1Gb set?

Probably the most demanding thing I do is gaming - no AutoCAD or video editing.

 

[Reality|Bites]

Just installed another 4GB of memory and installed W7 today, I have 4GB free from boot up. I probably only needed 4GB but what was I going to do with my existing 2GB?

I had the choice of another 2GB for £44 or 4GB for £64, what would you have gone for?