Ive been with Nvidia for a long time.... since the 64mb GeForce 2's were being bundled out at £40 a throw... until recently when I spilled coolant all over my relatively new 6600.
I decided to shop around on the net and look for a card that wouldnt cost the earth but still do the job as good/better than my current (fried) card...
And I found....
Click here to view page/price/info
Had the card a couple weeks now.... cant notice a huge improvement playing half life 2 using the 'recommended' settings.. but turn on the overclocking software... and you can set everything to maximum without a worry in the world.
If you've got £150 to spend ($300 or thereabouts) then this card comes highly recommended... although I do believe the AGP version of this card comes at a higher price and doesnt offer quite as much performance pound for pound as the PCI-E one does.
Now Im no graphics genius or anything... but my bro's comp (running the exact same spec as my own with exception of graphics card) runs its graphics through a Nvidia 5750 128mb.... which only emulates DirectX 9.0 through the software but is infact just a Dx8.1 ... it struggles on full quality settings and simply cannot create smooth textures & lines... which the x800 manages to do perfectly.
Heres a screenshot showing what the x800 can do playing Riddick... its gotta be agreed that for a card costing under £150 its definitely upto the job for high-end gamers on a mid-end budget.
Nvidia... good for ease of use with the software/drivers... plays games like Unreal Tournament 2003/2004 really well (best suited to that graphics engine) but struggled on Doom3 at higher settings where the Radeon makes mincemeat of it.
Upto you, but Ive been swayed over to Radeon since getting one... I miss the digital vibrance option with the Nvidia's amongst a few other goodies but all my games look and play best on the Radeon.. which was similarly priced to my 6600.