802.11ac, sometimes referred to as 5G or gigabit Wi-Fi, hasn't been finalized and Apple seldom if ever speaks ahead of time about the incorporation of new technology into the iPhone, iPad, or Mac lines, but they were aggressive in adopting 802.11n while it was in the draft stages and 802.11ac appears to have even more to recommend it.
The new 802.11ac standard achieves much faster wireless networking speeds than the existing 802.11n specification (in use on the latest Mac, AirPort and iOS devices) by using 2 to 4 times the frequency bandwidth (from 80 to 160MHz), more efficient data transfers through sophisticated modulation, and more antennas (up to 8; existing standards support up to 4, while Apple's Macs currently use up to 3).
With everything from AirPlay to iTunes Wi-Fi sync to the downloading of content from iTunes Netflix and other online repositories becoming increasingly front and center in iOS, better, faster Wi-Fi will be huge plus. (Especially if when we see the eventual move to 1080p content on the rumored Apple TV 3.
The link below says Apple's working on 802.11ac, though the article doesn't say where that assertion comes from. Still -- I want it, and hopefully we'll indeed get it sometime this year if not the next.