the only benefit motherboards give in gaming mostly are it's SLI/CF capabilities and it's overclocking abilities. SLI/CF isn't worth it if each lane runs less than 8x. less then that, you're better off getting a new single card GPU. less hassle with microstuttering that way.
Ivy Bridge is an LGA1155 CPU. the rampage IV is an LGA2011 motherboard. most motherboard manufacturer's websites has a list of supported CPU's specific motherboard models are compatible with. ALWAYS check them. some may need a BIOS/UEFI update.
32GB is completely pointless for gaming alone. 4-8GB is the sweet spot. when the time does come when games need as much RAM, assuming there will never be a DDR4 or the like, your build would be too old that you're better off building a new PC. that and upgrading RAM is one of the most easiest upgrades to make
Ivy Bridge runs hotter than Sandy Bridge when OCed up to a certain point, usually when you have to raise the voltage in the 4.3-4.5Ghz range. but it has better performance per clock than SB. the 3930K is Sandy Bridge-E, a completely different Socket than Sandy Bridge. personally, i don't recommend them for gaming, as the price/performance ratio just isn't worth it.
i really cannot recommend you getting an i7 as the boost from 4 to 6 cores in gaming is only a few fps. stick with an i5, but that's up to you. when games do fully utilize 6 cores, it doesn't necessarily mean a 4 core will perform badly. the i3 and Pentium, dual cores, are still decent gaming CPU nowadays.
and about future-proofing; moderation. 3-5 years is the most your PC will last, assuming nothing vital breaks (something will, i can assure you that). look at the Phenom II series; 3-4 years old, mid-range 4 cores CPUs and still a solid CPU for gaming. maybe not the best now, but still solid. and it looks like it has a good year or two ahead of them left. future proofing is completely unpredictable, especially with the upcoming PS4/Xbox720 (console hardware plays a role on the kind of game performance you will need), and spending more cash can only do so much. by the time your build starts struggling to play the most recent games, and it's time to make a new PC, will you be happy to know that you spent say, $3000 for a build that was always meant to last for 4-5 years, or saved half as much at $1500 now, while saving up the other half for a future PC 3-4 years down the road?
an overclockable i5-3570K, and a high end GPU (GTX670/HD7970) now MAY last you as long as an i7-3930K, and the same GPU. when it starts to show it's age, you can OC, and maybe buy a new GPU or grab another one of the same GPU you currently have to run in SLI/CF. that should give you an extra year or two at best