Which one!?!

Hi,
I've recently got a nice little bonus at work and thought i'd spend it on a new graphics card for my pc. Just wondering what you guys think is the best option ( I can afford about £150)

My thoughts are:
-Add another Radeon 1950 Pro to my machine in crossfire (around £135)
-512mb 8800 GT (£136)
-256 8800 GT (£117)

or anything you think is good...
I would go for the crossfire due to the lack of hassle selling my old one but will I see any real difference?

Any help is great guys and gals, cheers

512 8800 GT is the best way to go.

if you can get an extra x1950 for under 70 l would say why not but the 8800gt is the way to go

Personally I would go for the 8800GT myself.
Only thing I don't like is that all game don't support Crossfire or SLI.
Who says you have to sell your X1950......Keep it incase something happens to the "NEW" card......RMA's can take quite a few days....even a couple of weeks .......so why have no comp.
I just ordered the 8800GT ($269.99) below,and I'm keeping my 7900GTX...Just in case

Specs:
65nm GPU boosted to a mind blowing 720MHz
3 phase power design for extreme overclocking
Incredible fillrate of 40.3 pixels per second
2GHz Memory clock
Superior Cooling lowers temps as much as 25c



Features:
Full DX10 support – Full Direct X 10 and Shader Model 4.0 support delivers uparalleled levels of graphics realism and film-quality effects.
Unified Shader Architecture - Combines vertex, pixel and geometry shaders for an overall more efficient architecture.
NVIDIA Quantum Effects – Enables a new level of physics effects to be rendered and simulated on the GPU.
128-bit HDR with FSAA – Realistic High Dynamic Range lighting, now with support for anti-aliasing!
Built for Microsoft Windows Vista – Fourth generation GPU architecture gives Windows Vista users the best possible experience with Windows Aero 3D user interface.
PCI Express 2.0 – Provides support for Next Generation PC Platforms
Blu-ray/HD DVD Support – Featuring revolutionary second generation NVIDIA PureVideo HD Engine