I concur with TheGoatMan, if your choice is either FX5200 or R9600, definitely go with the Radeon.
I have an R9800 Pro and I am quite happy with it. I have been an nVidia fan ever since the TNT2, but the FX range has severely disappointed me. A friend of mine has an FX5600 with the same mainboard and CPU as I do, and the framerates he gets in the same games are at least 40% lower than mine.
On the other hand, I would avoid going all-out for 256MB on the graphics card. Sure, more is supposed to be better, but there are simply no games today that take advantage of so much space, and on an AGP 4x board you'll be wasting money.
I know, Doom III and Half-Life 2 will be demanding, but I am sure 128MB will get you by just fine.
Besides, if its bragging rights you want, then you need a Radeon 9800 XT. Now that will give you the overboard feeling you're looking for !
Pascal.