Which is better?

[drone]

Yeah, I'm not too clear on what the 9800 actually is. I've read several people claiming that it's just a renamed 8800. If I cared more, I would really look into it.

The 48XX series is newer and more efficient, in any case. Judging by the performance charts I've seen, you won't regret steering clear of the 9800.

Yeah, it's Wikipedia, but these 2 pages are gold when comparing differences between graphics cards.
Comparison of ATI Graphics Processing Units
Comparison of NVIDIA Graphics Processing Units