In terms of value per $ spent, I'd vote for the 9000Pro. However, if u want the BETTER card then go for the Ti4200. IMHO, the 9000Pro does beat the Ti4200 in some areas (as mentioned, anisotropic filtering). Just downloaded the latest drivers for 9000Pro and they work awesome, bumped up my 3DMark2001 SE quite a bit. No OC-ing even!
Save up for something that'll really make a difference to your system, new mobo or processor and then dream about a 9800