the Win7 integrated backup only seems to work on the hdd it was originally installed on...trying to put it on a different hdd won't work out so well. .
Do you have a specific example that you've tried? Microsoft DID make some pretty major changes in Win7 backup, and, judging from MS' Vista/Win7/2008 Backup support forum, some of these changes are causing surprises.
Vista's built-in system backups ("Complete PC Backup") would only do restores to disks that were the same size or larger than the original disk and could be very picky. Server 2008 R2 restores can be done to a smaller disk than the original disk IF the data will all fit. Presumably, Win7 is similar, but I haven't tried it. There's also a manual work-around for the disk-size thing in Server 2008, at least.
And, yeah, I've done some of these backups/restores in Server 2008/2008 R2 and doing the restores can be challenging at times.