Here's what I bought, these looked extremely cheap and fast to me!
http://www.newegg.com/Product/Product.asp?Item=N82E16820145539
That's a nice little walk! A mall with a place like CompUSA or Circuit City will charge more retail for memory there anyways. Being that HP is using Asus boards the memory should work ok. But a 2gb purchase would go even further for gaming and even any plans to upgrade to Vista later. When going from a matched pair of older Corsair DDR400 memory to 2gb of Kingston Value Ram the performance increase was noticed here.