How long (time/duration) should a complete restore on an iMac from Time Machine take? I was getting long boot times when I would log onto my account and even my kids' accounts on my iMac (2008 Intel Core 2 Duo).  Then I could not launch Disk Utility and other standard, pre-installed software (including Accounts under System Preferences).

I started the process with Snow Leopard to restore from a Time Machine backup, but it says it's going to take 56 hours! My HDD is 500GB but that seems like an excessive amount of time.

What would be the usual time range?

I started it last night, but it came back to the "Language option" as if it restarted the disk.

Ideas?
After reading some Apple support threads on this topic, I found a hopeful tip that (for some reason) connecting the TM drive before launching Time Machine System Restore limits you to USB 1 speeds (and thence multi-day time estimates), but attaching it after gives you full USB 2 speed.  

After suffering through about 1% of a backup estimated at 60+ hours to complete, I tried this and it indeed the projection is much better.