Dan, when you plug in your Android phone to your PC to charge it, it will give you 4 choices (at least my HTC Desire does)
Charge Only
HTC Sync
Disk drive
USB tethering
and you click one, and select "DONE"
What they do is pretty obvious, but its:
Charge Only does just that ... uses USB power, but not data
HTC Sync only works with Windows SW for now.
Disk drive makes the phone's data show as a USB Mass Storage Device (memory stick)
USB tethering makes the phone a modem for internet access using your data plan, amongst other options
When you choose option #3, Disk Drive, then you can access all the files on the phone.
Now, I design embedded computers that run Linux, but I dropped out of SW development back when C++ was new, so I'm not the expert but I think options to sync include:
1. MANUAL drag and drop
2. SEMI-AUTOMATED: After backing up the first time, use rsync (sp?) to sync up files without copying everything (only changes) from command line
3. MORE-AUTOMATIC: take the rsync backup command and put it into a Bash Script, and give it an icon on your desktop
4. FULLY AUTOMATED: catch the dbus message that your phone has been connected by USB ,and have some code automatically launch your backup/sync script.
I can't help you with HOW to do #4 (my son could ...) but its doable.
And you'll want to make the "disk drive" option the default when you plug in.
I hope that helps...