I'm on 3 Mb down/ 768Kb(?) up with Comcast for $20/month, not just because I'm cheap, but because I refuse to give those goddamn bastards even a penny more than I absolutely have to! (The nanosecond Google Fiber finally shows up I'll be telling Comcast to suck it, regardless of what Google decides to charge.)
Anyway, so far it's been pretty much fast enough. Bulk downloads can take a while, but gaming, VoIP, Netflix, and (I think) Netflix + Youtube at the same time have been fine. Admittedly, I haven't paid much attention to bitrate; the streams probably aren't HD most of the time.