Okay, kicking Alaska and Minnesota aside for a minute because I can't find any good polling data (and I'm using an outdated poll for Arkansas).
If we assume a straight proportional, no minimum threshold rules for every state, we get:
Trump 194 delegates
Cruz 138 delegates
Rubio 70 delegates
Kasich 14 delegates
Carson 15 delegates
(though my math seems to be off somewhere, still leaves about 100 delegates unaccounted for of 529 when you leave out MN and AK).
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However, Virginia is the only state in Super Tuesday without a minimum threshold to receive delegates (and thus likely the only state where Ben Carson will get a delegate).
The minimum thresholds are:
Massachusetts: 5% (Carson is polling at 3%)
Minnesota: 10% (Not sure what Carson is at, but I can't imagine it's above single-digits)
Alaska: 13%
Oklahoma, Arkansas: 15%
Texas, Georgia, Alabama, Tennessee, Vermont: 20%
This has real repercussions in several states. Kasich is liable to be shut out of delegates everywhere but Virginia and Massachusetts. Even with a 10% showing in Vermont, he won't qualify.
Rubio could be conceivably be shut out in Texas, Tennessee and Vermont, despite placing 3rd in TX and TN and 2nd in VT. He's at risk of being shut out in Alabama as well.
Cruz could be shut out in Alabama(!) and Vermont.
Vermont could, incredibly, go entirely to Trump just because no other candidate hit the 20% threshold. However, the polling numbers of Vermont leave a whopping 27% undecided. Rubio would likely pick up enough to push him over 20. Not as clear for Kasich and Cruz.
Likewise, Cruz is below the 20% threshold in Alabama, and Rubio is in serious danger of slipping below it. A little bit of surge by...well, anyone other than Rubio could wind up handing the entire state to Trump by virtue of the 20% minimum.
Being shut out of Texas would hurt Rubio bigtime, and likely benefit Trump -- if an urban district went for Rubio but he was ineligble to receive their delegates, it would go to the 2nd place finisher in the district, which would likely be Trump.
A number of states turn into a winner-take-all at some threshold, typically 50% (66.67% for Tennessee and 85% for Minnesota), but the only race that has any polling numbers above 50 is Massachusetts (Trump's latest result was 51), which does not have a WTA clause.
Once you drop Kasich and Carson out of consideration, and account for the minimum thresholds, it's going to be a mixed night for Cruz and Rubio. Rubio will likely beat Cruz in a number of states that Cruz should be expected to win (and by win, we mean "come in 2nd place to Trump") but will likely wind up with a lower overall haul of delegates. Cruz will win Texas (but is unlikely to win all the districts and get a sweep), and in other states he could well fail to win a district, or only win one or two districts and a meager number of delegates.
Bottom line prediction:
Trump walks away with about 450-500 delegates tonight. Less than 450 means Cruz and/or Rubio had a better night than expected. Over 500 means he swept most states and possibly won Texas.
Cruz will get between 90-120 (almost entirely from Texas). If he loses Texas, more on the order of 20-40, and possibly less than Rubio.
Rubio gets about 45 if he wins Minnesota, and maybe 15-20 if he doesn't.
Kasich gets 2-3, from Virginia and Massachusetts. Probably drops out.
Carson gets 1 delegate from Virginia and promptly stores him in a pyramid, and insists that there's still "a chance for people to wake up".
Now, the fascinating bit is that as I pointed out, Cruz will likely have the better delegate count while Rubio will have more 2nd place finishes. Cue an uproar about the fairness of GOP primary rules and minimum thresholds, and neither candidate will drop out. Meanwhile, Nyarlotrump will be sitting back and grinning as the GOP devolves further into chaos. I'll have to make popcorn.