fork over an extra dollars for the e6600 please... the more cache is worth it

Quote from AMAT:
Hi:Andrew
I am thinking of doing the same thing first time ever. I don't have much experience on PCs. I wonder if you can kindly enough give me some hints on the following questions:
1. where do you get your parts? It seems to me you got a good deal. online canadian sites or american.(I am at Toronto) or local stores?
2. you said you go with Vista64, Do I need a 64bits motherboard to support Vista64 or 32bit mobo will do.
3. How can I get OEM Vista64? I noticed OEM is much cheaper than retail one.
4. Can 500W power supply support 4 24" LCDs?
Thanks