There aren't any budget cards coming out at the end of November. Nothing at all under $200. MSRP for the next generation cards starts at $220-250, so that means a street (online) price of $200+ at the "low end". The real next gen budget cards aren't going to come out until 2008. The cards coming out next month WILL be more expensive than any 2600XT, 8600GTS or X1950 Pro (even the 512MB versions).
The problem with the 2600XT, even the GDDR4 based variants, is that the memory interface is only 128-bit. So having 512MB of memory is worthless because the cards cannot handle the high resolutions or the large textures that would make use of anything beyond 256MB. While the 2600XT GDDR4 beats an 8600GT by about 10-15%, it costs as much as an 8600GTS, which it's only on par with. It's really not a very good value, just like the 8600GT and GTS.
If you want a card RIGHT NOW, and it has to be under $200, get an X1950 Pro 512MB. It's consistently 20% more powerful than both the 2600 and 8600 cards despite using an older architecture and GDDR3 simply because it uses a 256-bit interface, which makes playing at 1600x1200 as possibility. The 2600 and 8600 cannot do that because their 128-bit interface bottlenecks their performance.
Someone might say "Well, the X1950 Pro is only DX9.", but if you've seen the benchmarks of the 2600XT and 8600GTS, you know that you don't get playable framerates in DX10 with either of those cards, effectively making them DX9 cards as well.
The best option is to save up another $50-75 and wait a month. ATi is supposed to have a $200 card (RV670 based) that will beat the 2900XT (RV600). It's direct competitor, Nvidia's G92 based 8800GT, is clocking in at 90% of the performance of an 8800GTX in 3DMark06. As a result, Nvidia is actually adding shader units to the 8800GTS (from 112 to 128 like the GTX has) and is no longer producing the 320MB version, leaving only the 640MB version remaining, so that the 8800GTS isn't less powerful than the less expensive 8800GT, which should also be around $200. Sucks for anyone who just bought a GTS or GTX, but it's good for anyone buying a card in the $200 range in the next month.