Lots of good info has been given so far about this, so I will just repeat some of to reassure you.
The more memory and the faster it is the better off you will be( I would suggest 512mb at the very least ). Lots of HD space is improtant, but how much really depends on what kind of editing and how much you plan on doing.I myself have a 160gb 7200rpm seagate barricuda.(concidering various games, programs,etc., I would suggest at least 80gb so you dont end up running out of room.) HD speed is crucial as well and a RAID config would be worth concidering.
As far as cpu type and speed, In my own experiences with various low end and midrange AMD and Intel cpus, brand hasnt seemed to make a great deal of difference as much as the speed of the cpu.( that purely my experiences and others may say different)
I do LOTS of video editing with the system in my sig(dvd ripping, burning, dv conversion,DiVX to Mpeg2,etc.,) and I am very pleased with the performance it gives me. Im actually doing a conversion as this is being typed.
lol
And example of the speed I getting out of this setup.(btw, my processor is current running at the stock speed and not 2.4ghz)
:
This conversion is being done with TMPGenc Plus.
-Im using a .d2v file that was created from a .99gb VOB file,720x480
-A 1536kbps wave file,16 bit,2 channel stereo, 48khz
To put is short its being converted to this/-Super Video-CD NTSC Film (MPEG-2 480x480 23.976fps VBR 2150kbps, Layer-2 44100)
This is with most of the settings at best quality,fit to screen(keep aspect ratio)etc.
-min. bit rate 1000kbps, avg bit rate 2150kbps, max bit rate 2520kbps.
- this file is being converted in 3 parts.
I have 30 processes running at the current time on my pc including the conversion program, a firewall, and program that is currently downlaoding. My approximate conversion time for all three parts is 6-7 hours. The audio size is a big part of this time because a DiVX approx. 1.4gb with mp3 sound takes about 2-3 hours. This may not be fast enough for some, but for the ammount of money I have in my setup, Im satisfied with it.
Hope this helps and sorry for the large post.