Graphics card help!

Right I can take back the GF 6200 I got and get a refund allowing me to choose another card, I know I was recommended the GF 6800 but which model?! I have an AGP slot not PCI express so it's proving a bit difficult. I've found this model:

http://www.komplett.co.uk/k/ki.asp?sku=317265&cks=NWP

Does that look ok? I want something high-end whilst not costing too much, £200 and a bit more would be enough. I also don't want a dud model with a lower clockspeed than other models of this type, if you get where I'm coming from...

I'm useless with GFX cards

http://www.overclockers.co.uk/acatalog/6800_Series.html

They all look mighty fine..

Quote from killertomato

The BFG GeForce 6800 GS OC (1st one) seems to deliver the biggest bang for your buck. Apart from the fact that it has higher clockspeeds, it also has a lifetime warranty.Also be sure to check it's requirements. You might want to buy a new power supply.

My relevant specs are:

Pentium 4 3.2GHZ

1GB RAM

DVD-RW / CD-RW

120GB HD

Not sure what the powerpack is, I know it's very powerful though, I'll have to double check...