Usual graphics upgrade question…

I guess this is the best place to ask for some opinions on this one.

I currently have a Shuttle that is running an AMD 3700+, 2GB of decent DDR400 and the following graphics.

AGP slot = ATI 256MB X800 XTPE
PCI slot = 32MB ATI Radeon 7500

This little lot is driving a Dell 24” W/S off the X800 and 2 Dell 19” TFT’s off the PCI card.

I have just managed to get a decent deal on a 4600+ X2 that will be going in the rig and it got me thinking would there be any benefit of upgrading the main graphics at the same time?

I was looking at the Sapphire X1950Pro 512MB AGP that seems to fit and run in the said Shuttle with ease.

I don’t intend to use Vista on this rig as Vista does not support dual monitors when one of the cards is an old PCI card so I can’t see things like DX10 being a big deal (not that the X1950 supports it).

As this is the better part of a £150 upgrade do people think it is worth looking at?

Am I right in thinking that the X800 still has some headroom to step up to the 4600+ or am I running it at about its max right now on the 3700+? Is the 4600+ not really going to get the best out of a X1950 Pro? The old reviews I can find are not all the helpful on this mark and tend to be synthetic anyway .

As always, thanks for any comments.