I would personally go with 2 x 1 GB of DDR400, it will slow down to DDR266 speeds, and it will allow you to use the RAM if you ever upgrade to a socket 939 AMD board. Plus, it will be almost the same price.
http://www.newegg.com/Product/Produc...82E16820231039
As for AGP, most cards are AGP 4x/8x compatable. AGP 4x won't be that much slower than AGP 8x, so you can get some pretty good gaming with a good card.
http://www.newegg.com/Product/Produc...82E16814170082
http://www.newegg.com/Product/Produc...82E16814102606
If you are in the US, Newegg is a great site, with great service, and in the UK, misco.co.uk is the UK version of Tigerdirect.