I'm looking into speeding up my Windows 7 backup. I have it creating a system image of my system drives/partitions (320GB in total; about ~40GB free [lots of Steam games...]) once a week.
I have found that there are some registry keys located at
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\ which allow you to exclude files/folders/file types from the backup. There are already a bunch of default entries under the three keys at that location in the registry. However, they are all entries that MSFT/Windows knows can be excluded (I doubt third-party apps are adding entries there).
This functionality is already baked into OS X's Time Machine and setting up exclusions in Time Machine is ridiculously simple and since Microsoft did a poor job of exposing exclusions to normal end users in Windows 7 it seems they expect us to fill in the gaps.
My eventual goal is to write an app to manage the entries under these locations to give users (or just myself if no one else is interested) control of which files can be skipped during backup. However, I'd like to start out with a list recommended files that I can safely exclude from backups so any help is appreciated.
Edit: I've just done a bit more reading and found that exclusions listed in the above keys don't affect block level backups (which is what Windows image backup uses). The exclusions are instead honoured at restore time by being deleted just after restore. This doesn't help for saving time during backup and/or reducing backup size...
I'm open to other suggestions (alternative backup software...?)