I had a look at the laptops you wanted on the website. The Radeon equipped laptop you are looking at is the Radeon 9000 IGP. It is not a dedicated graphics card such as the Radeon 9000, and it uses system RAM to hold its video stuff. Therefore; it reduces the amount of RAM available to the system, and the performance of it will be a lot slower than the dedicated graphics solution. The other laptop that you were looking at, the R3000Z, has a dedicated NVidia GeForce 4 420 2 Go graphics card in it. It will not chew up any system RAM, and the benchmarks say that the NVidia card is a lot better then the Radeon one. Also, the Athlon 64 3400+ will mop up any Celeron or Pentium at gaming! I reckon that you should go for the R3000Z for the following reasons:
1.) An Athlon 64 3400+ (Killer Gaming Processor!!!)
2.) NVidia GeForce 4 420 2 Go 64mb (Not sucking up your ram, much faster then the Radeon 9000IGP!)
3.) It also comes with a special gaming offer, you'll have to look into that.
All in all, the R3000Z is a much better laptop then the R3000T. However, I should point out that both Video cards in both Laptops are a little outdated. You might want to look at some other laptops for some better cards. Try to go for the mobile versions of the Radeon 9600XT, or even the 9700 Pro, which is a real killer of a card. Also, you could look at the NVidia GeForce 5600 or Better. However, the fastest graphics card for the laptops is the 9700!
That's not to say that the laptops you are looking at won't be any good. I can assure you that you could play any game out there at the moment, but you might have some problems with upcoming games such as DOOM 3!