In DX8 games, the 4200 is better, but my concern is that without support for dx9, the 4200 will be a dinosaur soon. The 5600 kills the 4200 in DX9 Benchmarks, especially with the FSAA enabled. Although the 5600 is not the ideal solution, it seems like the best choice to fill a gap for a year or three until I have more $ to dispose of. Let me know if I'm wrong. And no, I can't afford a 9600 Pro, even though that would be a sweet budget card. $100 is my wife's limit.
Where there's a will, there's a way-even when it comes to screwing up.