BTW, you can't fully share TTL flashes between an F3 and any other Nikon due to the proprietary mount unless you get the usually very expensive Nikon AS-17. So getting another F3 is not a bad option.
Getting the FM2/FE2/FA/FM3a gets you a smaller lighter body with higher flash sync speed and higher shutter speeds - and other features as already mentioned.
Nikon's smallest slr - the FG (EM/FG/FG20 lineup) is worth a look see.