Do new DDR2 Power Mac's require Mac Specific RAM?

My father is a graphic designer and is about to buy a new Power Mac either Dual or Quad core rig and i'm trying to find him ways to cut costs yet have all the goodies he needs in it. (he's a software guy.... hardware ignorant. I'm also a systems consultant yet have minimal MAC training)

The two Macs he's considering both use DDR2 PC2-4200 RAM and I wanted to know if you have to use the Mac specific memory (actually they offer Kingston at macmall.com... bleh) or can he use any quality ram (Corsair) of that specification?

Here is the kit for Mac that he was going to buy which runs around $250 for 2gb.

http://www.ec.kingston.com/ecom/configurator/partsinfo.asp?ktcpartno=KTA-G5533/2G

Then on the other hand, i was looking on pricewatch for the same spec of memory but whats used in PC's and it only costs $130 for some Corsair Value.

I'm not sure if you guys even deal with new macs... but from my experience with PC's... i doubt i'd do any damage if the PC2-4200 for non-macs would actually damage a mac. I'd think it just wouldn't post and i'd have to RMA it for something Mac specific.

https://www.monarchcomputer.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=M&Product_Code=140122&AFFIL=pricewatch&NR=1

I know Macintosh tends to use hardware specific components which usually are mac-only, but now that they are using RAM which seems to have similar specs to what PC's use, are PC memory chips compatable with the new Mac's? I know components like video cards wont work because of firmware that is specifically mac, but RAM seems to be far less complicated and may work, unless Mac decided to put the notch in the chips at a different location or changed some pin-out locations just to keep their hardware propriatary (spelling?)

Any imput is greatly appreciated.

-Andrew