Given NVidia's better driver coding track record, I'm confident the 8800GTS will be made DX10.1 compliant (with maybe some emulated DX10.1 features). I'm not conserned. Besides, there is no games even on the rumorwheel about a DX10.1 required game.
nVidia's XP driver track-record is proven, but their Vista drivers were an absolute debacle upon release. ATI were way ahead of them. Shame about their sub-par hardware.

Honestly, I can't see nVidia going to any great trouble to update the 88-series for DX10.1, It wouldn't be a good business move.
Why would they spend R&D and Dev-time on x.1 emulation when they can just push the rumoured soon-to-be-released G92 core series and make far more money?
What ever the 8800GTS has troubles with AT FIRST will be bridged by new drivers by NVIDIA. Within 3-6 months at most after Crysis' launch, you'll be able to run it on maximum settings with DX10 even if the developers of the game don't launch any new patches to fix the lag problems.
Sorry Rain, but I seriously doubt that. New Forceware drivers don't make a 7900GS perform like a 7950GX2.
New drivers certainly won't make an 8800GTS 320 run like an 8800Ultra, especially with the limiting factor of 320mb of video memory.
And that's before you even consider that an 8800Ultra lags in Crysis on settings below the maximum.
Software optimisation (of both the drivers and the game) can only do so much, it won't work miracles.. Sadly.
Overclocking might get you somewhere, but don't expect more than a few frames extra per second.
Besides, there is no games even on the rumorwheel about a DX10.1 required game.
There aren't even any upcoming or released games yet that require DX10, but developers aren't going to stick with 10.0 forever.
They didn't stick with DX9.a forever - Any game that requires DX9 these days explicitly demands DX9c because of the inherent benefits of updated code.
Sure, no games
require DX10.1....but then, we could probably get Crysis running on a 6600GT if we handicap the engine like when they got Doom3 to run on a Voodoo2 in wireframe with all texturing renderpasses disabled, or Oldblivion running on the nVidia FX series.....but that puts you in the territory of not playing the same game and begs to question the point of playing modern games on old hardware when the core gameplay is the same as ever anyway.
DX10 is nice already, but it takes hell lot of programming when a Direcx comes out for hte first time I think, since a lots is new, not to mention games get harder to make each year with more and more technology needed.
That's already long been true of anything from the late DX8 and whole DX9-era.
When games started using multiple render passes for texturing on a single model, things got complicated.
No longer do skinners just have to produce a raster-layer texture, but also bump-maps, normal maps, lightmaps, parallax maps, etc etc.
Texturing for X3: Reunion, for instance, is a bloody nightmare, take it from me.
Thing is, that's nothing new to DX10, that's been the case for a few years now..
And yeah, it may be extra work, but the results (with the addition of some talent and skill) are worth it. I've been wishing for years that Redemption's engine supported additional surface maps for models, simply because it would look incredible.
But then I remember that the NOD engine is based on Quake 2.

My own plans for hardware upgrades were set back today by the painfully-expensive purchase of the book "Big Java 3rd Edition" for Uni....but it's so worth it.