I've been trying to come up with a video editing/DVD authoring system (mainly DVD authoring).

my parts list:

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Intel Pentium 4 2.4BGHz 512K 533MHz CPU Northwood P478 Processor

ASUS P4PE/R/L/SATA Motherboard for Intel P4 478 Retail w/ Intel Hyper-Threading Technology, SATA, Onboard LAN, Firewire IEEE1394, Serial ATA SoundMAX Digital Audio System

Maxtor 120GB 7200RPM Hard Drive 8MB OEM

512 MB Crucial DDR C2700 • CL=2.5 • Unbuffered • Non-parity • 6ns • 2.5V • 64Meg x 64

WD WESTERN DIGITAL 40GB 7200RPM EIDE HARD DRIVE MODEL (for extra support)

ANTEC Performance PLUS Model PLUS1080AMG- with Antec Original TRUE 430W P4 Power Supply ATX12V (a good buy or no..?)

Cendyne or Sony dvd burner (lotta money )

M-Audio Audiophile 2496 sound card (for music editing)

Canopus ADVC-100 video capture card

Radeon 8500 video card (for not-so graphics-intensive games and such)

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I'm really dumb when it comes to cooling units, do I need just an extra fan or something like a heatsink...., ..., ? Already posted in the building computers advice forum. I don't plan on overclocking - at this point in time I can't afford it if something went wrong..Just a cooling system for a regular CPU and if I need a cooling unit for the harddrives and memory, too - I'd be glad to know..

You're going to need a heat sink and fan for the cpu, although if you buy a retail boxed version, it will come with these...

If you go with an OEM CPU, you'll need to pick up your own hs/fan and, in my opinion, this is an area not to skimp on.

A high quality heatsink is easier to install and probably will work a little bit better.

That said, I've seen people buy the cheapest heatsink they could find and have no problems at all...all depends on how comfortable you are with system building...