Time Machine Strategy?

I just finished a tough weekend of getting my Mac back. For whatever reason, it would no longer boot. I am running 10.6.8 on a 2010 MacPro.

I installed a new copy of the OS, and migrated, then updated the OS, and it froze. Back to the install disks, loaded, updated OS first via software update, then migrated and I'm back in action.

The migration took hours as the drive had a lot of data including large iTunes files, etc. 3TB drive is my main drive.

Is there a better strategy for one's OS drive and data files that would make a re-build less time consuming? e.g. Use the OS drive, and keep it smaller, say 1TB, just for the OS and apps, and then a second drive for data only?

I'm grateful Time Machine worked so well, just looking for a faster way to get going next time.

(Note - I have too many apps needing Rosetta to jump to 10.10 full time. Not ready to drop $hundreds on updated software.)