synchronizing hard drives

[Malcolm Hamilton]

Can anyone advise me how I can keep the hard drives of my two G4s 
synchronized (if that's the word)?  I have a Titanium and a G4 tower, 
side by side (except when I travel):  I currently use the Ti for most 
of my organizational tasks (e-mailing, calendar, writing projects, 
etc.), and the tower mostly for video editing (but because it's 
faster, I sometimes surf the web with it, etc.).  It occurs to me, 
though, that ideally I should have the same applications loaded on 
both machines, so if one should experience problems I can just switch 
to the other and carry on with my work.

Loading each hard drive with the same apps., prefs and files is 
within my capabilities.  However, what I'd like to know is the 
easiest way possible to synch up (not to mention back-up) both drives 
at the end of each working day.
The two computers are hooked up with an ethernet cable, so I know I 
can drag files back and forth.  But is there a simpler, more elegant, 
way to update - - in both directions - - in one fell swoop?

Software or hardware suggestions?  Any and all advice would be appreciated!
--
Regards,
Malcolm