Which Hard Drive?

I'm going to order my new Hard Drives tomorrow and want a few opinions.
I was going to order 2 x 500GB http://www.newegg.com/Product/Produc...82E16822148136 Together both of these drives will cost $240.
I've also been thinking about going with 1 x 1TB. http://www.newegg.com/Product/Produc...82E16822148274 This one drive will cost $330.
The 500GB drives are 7200rpm 16mb Cache and the 1TB drive is 7200rpm 32mb Cache. Do you think the 32mb Cache is worth the extra $90. If I go with the 2 x 500GB that would leave enough money to buy another 2GB RAM for a total of 4GB then I would load Windows Vista Ultimate 64bit instead of 32bit. Or instead of the 2GB RAM I might buy another MSI nVidia Geforce 8600gts and try my hand at SLi. Both of these options will most likely come later but I could afford one or the other now if I go with the 2 x 500GB instead of the 1 x 1TB Hard Drive.
Which Drive(s) would you buy?
2 x 500GB 7200rpm 16mb Cache
1 x 1TG 7200rpm 32mb Cache
_________________
Filing Cabinets Estate Fencing