The F5 is a great camera, but yes, it's kinda big. (This, of course, rules out the suggestion of an F4, which, if anything, is a bit bigger). The F3 is as as bulletproof as they come, uses a pair of silver-oxide batteries that should see you the better part of a year, handles wonderfully, utilizes a seriously-accurate, tight center-weighted metering system, and largely stays out of your way in the picture-taking process. Add to this that you can still get the camera easily serviced, either through Nikon themselves or through a host of independent service shops. (And, yes, the film advance is scary-silky-smooth, for what that's worth.)
What you end up doing with the F5 and flash is your business, but let's just say I think getting an F3 body isn't the worst idea in the world, by a long shot.
- Barrett