If thats your attitude then the $500 price difference shouldn't matter either then.
My attitude is that computer power (however you want to measure it) is growing quicker
than sensor megapixels, and therefore any complaints you have with sensors producing too big files should go a way at a similar rate. Yes, of course, you can always save money by sticking to yesterday's tech, and that may be the best thing to do in many cases.
Compare the top-of-the-line harddrive of today (4 TB) with the top-of-the-line at the time when the 5D2 was announced (750GB). If you had no problems in fitting your 5D2 images onto the harddrive then, you should have even less problems in fitting the D800 images onto your hardrive today. Same goes for processing speed etc. Of course, you can do even better by using an even fewer-Mpix sensor on a current computer, but that's a rather trivial and non-interesting argument.
You wouldn't believe how may photos I can get on a 16Gb card with my D30
About the CF card, I was thinking about a card I recently purchased, a 400x Transcend 64GB
(now $126 at BH). The reason I got a 5D3 instead of a D800 had nothing to do with the number of Mpix.