What would I lose if I needed to reinstall from a Time Machine backup?

Things which they were not restored and they were crucial, was:

• MySQL Databases
• VMWare Fusion virtual machines

The default backup exclusion list, can be found in:

/System/Library/CoreServices/backupd.bundle/Contents/Resources/StdExclusions.plist

Do not forget to check your excluding folders on the prefs as well ;)

Time machine backups most things I (and others) have done an upgrade of the OS ie to a new disk from a TM backup. I have also done a restore after my hard disk died.

To see what it does not backup go to System Preferences -> Time Machine->Options. I forget the defaults but they include various caches - e.g. ~/Library/Caches. I have added ~/.Trash

You can also see what it has backed up by looking at /Volumes//Backups.backupdb//Latest