Never a bad idea, and you'll get a real kick in the pants watching how the OS runs on solid-state!
I went this route, and it seems to do very well:
1st drive - 240Gb Corsair Force 3 SSD C: drive for Windoze 7 64bit Ultimate, Office 2010, Waterfox, Adobe Master Collection CS6, and my FPS games.
2nd drive - 1.0Tb Western Digital Caviar Black 7200rpm/64mb cache partitioned into D:/E:/F:/G: drives for slower apps, media, downloads, and archival
3rd drive - 64Gb OCZ Vertex II SSD H: drive dedicated for just Windoze 7 pagefile and print spooler (Speed tweak)