To keep your price down, might want to go with a Duron, most people just using their PC's to get around online and visit web pages and such will not need anything more, even for gaming, a Duron is still capable of kicking out the FPS required...
I recommend Duron 850, because at least around here where I live the jump from 850-900 is not worth the money.
For a good case, check out
Antec cases, If you want a mid-tower you can get an SX840 or something along those lines, or if you want a bigger case, (Not quite full tower) check out the SX1030 and SX1030B. (Alienware style)
For memory most people in the forum will recommend you go with
Crucial because of their good price/good quality memory.
I'd say get a 256 stick of either DDR or SDR(PC133).. speaking of DDR or SDR, onto a mobo.. DDR RAM prices are very inexpensive right now so going to a DDR system is a good sensible thing to do except for one thing... the best DDR chipsets aren't quite out yet so it's advisable to either wait for a bit, or get a SDR based system and either stick with that, or just upgrade it in a little while, I have gone with an SDR system and feel it's plenty sufficient for virtually anything I want to do.... I'm going to wait until the KT266A chipset comes out and then upgrade my SDR board.
but for a good mobo, SDR - MSI K7T Turbo-R, EpoX EP-8KTA3, Gigabyte GA-7ZXR, Iwill KK266, ECS K7S5A
those are among the best SDR Athlon boards money can buy..
and for DDR I am not sure because I have never used one, but many people will recommend, EpoX EP-8K7A, Gigabyte GA-7DXR, ECS K7S5A, Asus A7M266
You really can't go too wrong as long as you don't just buy any cheap ghetto board, just make sure you pick a decent brand with a good rep!
Hope what i have written here helps you out... good luck, happy hunting..
