I would second a recommendation for Zen. Have never had a single outage (except when a BT guy did some work outside). Bulldog are worth looking at as well, especially if you higher bandwidth options as they packages that allow your bandwidth to increase during off peak hours (2Mbits) (6pm-8am), for a home user you get the best deal, a business package at consumer costs
I too use Bulldog and find their service very good - the customer service is very good also, which is very important. They have a good range of speeds for very acceptable prices. I'm not saying they're better than another because I've only used Bulldog, however this site is the bible for broadband, both for users and choosers:
So far migration to Zen is going well, although I'm a bit disappointed that their tech support closes at 5pm. Seeing as I'm at work all day I'm not sure how its going to work if I've got a problem when I get home.
Anyway, I will let you know what its like once I'm up and running. In the meantime, thank god I've got rid of BT, they were driving me MAD.
I use Pipex and have had very few problems,
But can reccomend Demon, I used to work on their Technical helpdesk, and few can beat their service. they didnt do broadband when i got it otherwise would have used them.