If the speed of the Wi-Fi 802.11n spec isn't fast enough for you, you should celebrate the upcoming 802.11ac spec, which, according to Broadcom, promises speeds of up to 3x faster, with 6x less power consumption for mobile devices. Whether you believe these claims or not, the fact that the 802.11ac spec will be a big improvement over 802.11n is a given.
Broadcom‘s BCM 4335 chipset includes 802.11ac Wi-Fi, Bluetooth 4.0, and FM radio, as an all-in-one chip. Broadcom says that this chip is in “full sample mode” right now, and we won't get to see it in devices until early 2013. So I wouldn't get my hopes high about buying a phone with 802.11ac this year, even with a chip coming from Broadcom's competitors. After all, the 802.11ac specification has barely just been finalized.
Belkin AC1000 DB 802.11ac router
To take full advantage of the speeds that Wi-Fi 802.11ac offers, you'll need to have at least a 500 Mbps connection, up to 1 Gbps, and also a 802.11ac router, which are just now starting to show up in the market, usually at over $100. Furthermore, if you don't want to experience transfer bottlenecks, you'll need a very fast smartphone that uses one of the latest processors, to process all the data coming in, and a very fast storage module, to handle the data flood.
So when you get a 802.11ac smartphone next year, I suggest you go for the high-end ones, but that's only if you you have a very good Internet connection and you want to get maximal speeds on your phone. The high-speed net connection part might be a problem if you live in the US. The Google Fiber network sounds promising, and it will hopefully push the competition to adopt 1 Gbit connections as well.
But even if you won't have a high-speed connection or powerful device, you would still benefit from the much lower power consumption of the 802.11ac Wi-Fi chip.