Well, there won't be much difference between the ti4200 and the FX5200 in next gen (DX9+) games...
The reason is that whilst the FX5200 is indeed a DX9 capable card (meaning it supports the features), it doesn't do so fast enough... Thus most (if not all) developers treats it like a DX8 card, and has it running that path...
Also, if you're going for the FX5200, make sure you get the 128bit version, and not the 64bit version... The 128bit is an ok performer, whereas the 64bit is not...
My vote would definately go for the ti4200.
Some people claims it also has better IQ than the FX5200, but I can't vouch for that...