Computer Shopping, need help Options

Buying new computers is like buying new cars, I suck at both. I'm looking for assistance in finding some good deals for *new* or referbished computers, desk tops or lap tops. My price range is 500 or lower.

Currently I got my eyes set on a Toshiba satellite note book. It sports an Intel Celeron M Processor 420, 512mb DDR (wtf? direct drive?) memory, 60 GB, reads/writes CDs/DVDs and has integrated 802.11 b/g wireless LAN, and a 17'' screen. Basically while reading this ad I see 420 and the thing cost 499.99 after rebates. I understand it has 60 GB, can burn CDs/dvds and has wireless internet capability. - all things that are attractive.

Next thing I'm looking at is a COMPAQ featuring an AMD Athlon 64 Processor 3500+, 512 DDR, 200 GB, DVD+R/dual layer/DVD+/-RWdrive w/ Lightscribe technology (huh?), Windows xp media edition 2005, 16'' flat screen. So I read this ad as being about the same thing except its 449.99 and a desk top as a pose to a notebook.

Of these two which is the better deal? And do any of you know of any better deals. Keep in mind I'm not interested in buying from individuals. I am only looking to buy through some company.

Darkmage has good points you should consider when buying a new PC. It really depends on your needs but I'll suggest you build the specs yourself instead of buying the branded one. I spend about $1250 on a custom spec about 7 years ago for a middle upper performance PC and I only have to upgrade my audio and video card last year. I'd say, spend as much as you can so you don't have to upgrade anything much in the coming years.