Which router to get?

Hard to answer; you didn't state how big an area the router has to cover, nor if any walls or floors are involved. You also didn't state what the speed of your Internet connection is.

That being said, there are a couple of things to keep in mind. 802.11ac is not yet a standard, however, all ac routers communicate with each other and with all other ac devices out there (such as adapters). Plus, ac runs on the faster, longer reaching 5MHz bandwidth, rather than the more crowded 2.4MHz. Finally, all ac routers are also a/b/g compatible.

On the downside, they aren't cheap.

802.11n is currently the fastest standard out there. Keep in mind that on any wireless router, the stated speed is what is optimal. You will never see that speed because you will almost never be optimal. The actual speed will depend on interference, number of connections and distance from the router. The best thing you can do to increase the capability of any wireless router you buy is to carefully select the channel the router broadcasts on and the physical location of the router.

If you do decide on a specific router, I would suggest you look up some of the reviews before you commit to a purchase.

Good luck.