the 9700 is the latest gen card, the next gen are listed here
roadmap for next gen cards
ATI R350 & Nvidia NV30 are the next Gen by the looks of things like crazzy kopite mentioned, looks like they are coming out soon
couple of quotes from site
"GeForce FX 5800 (400Mhz) and GeForce FX 5800 Ultra (500Mhz) are the supspected new names for Nvidia cards.
ATI Radeon R350 is expected to be released in Q1, 2003. The R350 is expected to be an enhancement to the Radeon 9700's R300 core, manufactured on the same 0.15 micron process. Optimisations made to the core will allow higher clock speeds, and there are rumours that the R350 may noticeably outperform the NV30. The R350 is being released to counter the release of the NV30 by nVidia."
the 9700 is not exactly twice as fast, but it is faster than the 4600, but then again its also more expensive
good comparision review
so unless you are desperate for a card and want to pay top buck prices, wait until the release of these and either pay over the top for them or just get the then 2nd Gen cards for a better price than now
always best to buy 2nd gen computer stuff, as your losses aren't as great when you upgrade, especially if you upgrade quite often like me
I learn't my lesson about upgrading to the latest and greatest a long time ago!!, cost me £100's for that extra few % increase in performance and it's not worth it, unless you are rich enough to not be bothered
p.s. still a good price regardless

NJOY