Another apparently underreported bit of math I noticed last night: According to the CNN results, at least, all the Republican candidates put together got fewer votes (1,319,960; 100% precincts reporting) than even the lesser of the two Democratic candidates (Obama: 1,356,330; Clinton: 1,455,959; and that's with 99% precincts reporting, so there will be a few more). Granted, Republican turnout was probably somewhat suppressed by the presumption that McCain had things all wrapped up (which he now does). Still, this was in Texas! This could augur very well for the general election in November.
Added: I suppose I should compare the numbers in Ohio as well, for completeness. Their greater preference for Clinton meant Obama did get fewer votes than all Republicans combined. Republicans: 1,010,864; Obama: 979,025; Clinton: 1,207,806 (all 100% precincts reporting). Even there, the mean of the Democratic candidates' votes (1,093,415.5) beats the Republicans' total.
Updated 2008-03-06: This other possibility had occurred to me, but I didn't want to bring it up without at least anecdotal evidence, even if it does tend to support my own preferred candidate. At The Rude Pundit (shockingly profanity-free for once), there's talk of Texas Republicans not just staying home because McCain's the obvious winner, but getting out and voting in the Democratic primary for the candidate they think will be easiest to defeat in November, perhaps most often Clinton. "Republicans knew that McCain would win Ohio and since in Texas we have open primaries, the RNC, Texas Repubs and Rush had been telling all their zombies to vote Clinton because they think they can beat her. My own mother, who hasn't voted for a Democrat for 40 years, told me that she voted for Hillary because 'you know, I support McCain, so I voted for her like everyone else up here.' My mother wasn't our only contact to verify our suspicions." All things considered, while I certainly consider these counts a good sign for November, I'm certainly not expecting a 2-to-1 blowout in Texas then, either.