the only reason why P4s are better in video stuffs is that they use SSE2. AMD doesn't have any right to put that instructions in their cpus so if you're into video editing, just buy a 2.4C but if you're a hardcore gamer AND do video editing, buy Athlon64 3000+
buy a MSI mobo
Athlon64 3000+
kingston hyper x PC3200 2-2-2-5 256x2
sapphire radeon 9800 pro
a WD SE 120GB or a WD raptor 74GB
audigy 2
a thermaltake venus2(?) hsf
I assume you already have a case, psu, cd-rw, dvd drive, and etc.
It might cost you about or less than $1000
I'm an AMD FANBOY. Intel folks, watch out!