The Mobo uses LGA775, why don't get a Core 2 duo. Even the E4500 easily beats a P4. P4's eat up a lot of watts and push out tons of heat.
And for the GFX card why not this ATI 4650 http://www.newegg.com/Product/Product.aspx?Item=N82E168... performs better and more recent for only 10 more bucks.
Also the RAM is SLOW 400MHz is unheard of today at least get 667MHz. Also get 4gigs or RAM or max out your mobo if it can't support 4gigs RAM is real cheap but very important.
Why not get a 500GB drive? It'll make your PC last a while longer and your can find ones for $54 bucks.
Do NOT get 400Mhz DDR2... that stuff is way old and outdated. I'm surprised it's even sold anymore.... and you won't be able to run any processor that has above an 800Mhz FSB without overlcocking the RAM.... get DDR2-800 instead.
ECS pretty much sucks. I've heard nothing but bad things about them. Choose a different brand... like ASUS or Gigabyte.