There's a flood of second generation 820.11ac coming out these days. My advice is to wait a few weeks and see how things look like once the dust settle. By then you might also determine that you don't need 802.11ac support, or it won't fit your budget.
An RT-N66U would be more than enough to support your 50/5 connection if wireless isn't a priority. An RT-N16 would be too, but I'd recommend going with dual band if you can afford it.
Ended up picking up the N66u and going to flash it later tonight, but so far it works great with all my gadget and etc. a bit spotty for downstairs. But i have 2-3 weeks if i don't like it i can return and grab an ac68u. It's pretty funny, but i think if i didn't plug my old dlink 614 into the wrong ac adapter id still be using a router from like 2000.