A lot of people will tell you to go with AMD but if you want to stay with intel then I suggest getting one of the new 65nm processors. Here's the one I would get Link
For a motherboard this one is really nice Link
For memory just get 2gb's and you should be good.
Well your hard drive is really good so you dont really need a new one of those. Unless you want to get another one for storage.
These are my suggestions just if you want to stay with intel.