I'll stick with my alt-net ISP...
I just switched to a 900 Mbit/sec download/upload plan on my alt-net ISP and they gave me it for £27 a month on an 18-month fixed price contract (and have just sent me a new router which includes some 2.5 Gbps ports). They also do a 2300 Mbit/sec plan for £50 a month, but I doubt I'd need that sort of bandwidth for a very long time. It didn't help that BT Openreach and Virgin Media ignored my town w.r.t. "full fibre" for long enough that an alt-net was the first to offer it (and at much better prices than BT or Virgin).