The biggest new part that will be coming between now and then are the HD 4800 series cards. AMD seem to have struck gold with these chips and they are looking awesome. There might also be some leaked 45nm Phenom and Nvidia 9900 benchmarks by then but that's unlikely.
Here is a chart for the specs of RV770:
As you can see, RV770 will have support for GDDR5 memory running at up to a 4GHz effective speed, 480 stream processors and twice the TMUs as RV670.
And nobody knows whether these are genuine or not but I don't personnnally believe them:
A 9600GT SLI setup is nice but like all multi-GPU setups, you never know what you're getting. In one game, you may get almost double the performance of one card, and in another, performance can be abysmal. At least when you're running a single card, you know what performance you are going to get. Also the other thing is that it forces you to get an Nvidia board which don't have the excellent overclocking abilities that the P35/X38 do.
You might also want to consider a Phenom X2 when they are out. The 9850 X4 matches and sometimes betters the Q6600 in benchmarks and it's overclocking capabilities aren't bad either. 3.4GHz isn't too shabby, and you get CrossfireX support with the 790FX.
So you can expect even more from the Phenom X2, especially a black edition.