(In the UK) They're one of the BT DSL and fiber resellers, they're a little pricey, but completely awesome.
There's no filtering or traffic shaping of any kind, no restrictions on running servers, and they offer web-based constant quality monitoring -- by-the-minute graphs of bandwidth usage, latency and packet loss on the line. Ring them up and you're immediately speaking to a technically competent person in the UK, no answering machines, no outsourced support.
I'm on the FTTC service (VDSL). I get 76Mbps down, 16Mbps up to speedtest.net with an 8ms ping time, and it bears out pretty well in the real world too (8.5MB/s downloads from Steam, 30ms ping to Diablo 3, Rift etc). And I get 5 static IPv4 addresses and an IPv6 /48 (!)
I switched from Virgin Media a while ago. The AAISP service blows Virgin out of the water in every way, even the top tier 100Mbps option. Friends are especially impressed when we do a Skype video call and my side auto-adjusts itself to a multi-megabit HD stream (Virgin's connections have very low upload speeds).
No, this isn't astroturfing -- just a satisfied customer! :)