If you want a good card for about $200, the 6800 GS is a good way to go. For about $250, go with the X800 GTO2, as it can be easily modded and overclocked to X850XT PE speeds (provided that you get the R480 core with it).
For about $150 or more, go with the 6600 GT or the X800 GTO
this is in the wrong section, malbuc87uk, you should know this. the x300se will play Hl2 VERY VERY poorly. get a X800GTO2 and mod it to a X850XTPE. If you get a R480, it is guranteed to mod (as far as ive heard, all of the PCI-E variants modded sucessfully).