So I've got a hybrid right now sitting in the garage, next to my road and tt bikes. I have half a mind that it will either be a commuter, or a cyclocross, or something inbetween. Other than thicker knobbier tires & tubes, what should I look at doing?
I "transformed" a hybrid for CX recently, with little effort. From what I can see, you just need to put drops (with shifters) on it -- this can be expensive, so I actually just kept the straight bars that came on mine and turned down the stem and bars to get lower, and add some pedals you can clip into, and take off the water bottle. It looks like your cables run under the top bar, too. If that is the case, you want to re-route them above the bar (for easier carrying of the bike on runs). As best I can tell, that would do it, as long as the brakes have clearance.
Lose all the stuff bolted to the bars, make sure there are good plugs in the ends (I put quarters inside the grips) and get appropriate tires. That's the minimum.
Either you're built like magilla gorilla or that bike is completely mis-adjusted for anything more than a bar run.
That saddle looks a bit fat if you're going to bring it up into a more normal, aggressive riding position.
You'll want some clipless pedals and MTB type shoes.
Next you can change handlebars, stem and shifters. If you do that might as well go to work on that crankset. I'm guessing you've got 38 and 48 rings, those are fine and either keep both or just the 38. Remove the guard ring and the 28t inner ring, you'll never need it.
Myself, I'd just do the tires, fit items (saddle and pedals stay with the flat bar (ALWAYS do the fit items (nothing's more important))) and turn the crank into a double, just 'cause it doesn't cost anything.