Hmm let me break it down
CPU...Hmm I dont know much about core duo, so im say you definatly didnt loose, probley broke even.
Ram...You upgraded, you have more and its ddr2.
GPU...Im not too good with ati and espically not with the x1xxx series, but I do know the x800xl is about a 6800vanilla(possibly gt) and I would say since you loose vram even if the new gpu was faster 128mb of vram will bottleneck it..conclusion on GPU downgrade.
Vista...Wow, thats not gonna help at all, I have it and its nice, but it's a resource hogg unless properly tweaked.
HD...LOOSE I know its not listed but its where most laptops fail is their slower hd's, unless they have a really nice 5400rpm or an exotic 7400rpm, which I doubt looking at the other hardware it has it it.
All in all, Id say you loose in terms of performance, but I think the hit you take is worth the portability.
The GPU is good for a laptop. Only problem is that it probably uses hypermemory which means it will use up his ram!
HD.... well he didn't say whether it was 7200 or not, so hold off judgment.
Vista.. I agree. Uninstall and use XP. Better for performance and battery life.