IF you can put up with abit of slow times normally 10pm-1 ish i would say ukfsn, for example the office max 45 pack obviously 45gig peaks, and from 8pm-8am off peaks and all weekends you get 300gig and is £29 as its office its 832kbs upload.
You will drop to around 2 meg speeds from 10-1 but apart from that its fine, now am downloading at my full 475kbs now, it will only drop when the home peaks kick in at 10pm, they are fixed ip too.
Ping wise even in this time is fine as they cut everyone down too 2 meg when it gets hammered but they are having another central pipe installed soon which will help with that.