It was nice enough (but cold) to drive to work today.  Ran great on the way to work, but errands during lunch and after work I noticed cranking got progressively slower with each start -- culminating with a no-crank after getting gas.  Fortunately that was only a few blocks from my house so my wife was able to come and give me a jump.  Was thinking alternator so after a brief look at the wires I found the small black wire that's on the same terminal as the red wire was completely severed.  Looks like it got brittle from heat and just broke.  I'm guessing that's my problem - should be an easy, cheap fix!  Never thought I'd be excited about a broken wire.  

Great to hear it was such a quick fix. Savor it, they don't come along very often.