if you know about building PCs and know how to put one together, you can get a good PC up and running:
Pentium 4 with 3ghz motherboard/OEM CPU HT/FAN : $205 (1 year warranty on board, 90 days on cpu)
1 gig of DDR PC3200 ram : $100
80gig 7200RPM system drive : $70
300gig 7200 RPM data drive (SATA or EIDE) : $140 x 2 (if you want one for preview one for video clips)
DVD Dual Layer Burner - Pioneer brand : $60, or you can find it from $33 and up
Keyboard/optical mouse : $15
Firewire card : $20
17" used monitor : $80
external video monitor : $35 (commodre rca jack in, those are cheap and do the job)
Case with Power Supply 550watts : $40
Roland MA-8 Stereo speakers $90 (used can be found for $50)
That's basically a good DV Editing suite and it can handle the basic for HDV editing as well if you have a 3.2Ghz CPU instead (add $40), the above came out about $920
So, yeah, you can build a good machine for less than 1k (I have 3 of these), but the bottom line is what you are more comfortable with, a mac or a pc, they are all just tools, it's the editor that would make the wonders.
Obviously, if you are good on what you do, people would be impressed with the result but of course, depending your skill level and the goodies the computer that can offer you
