We are (OK, I am) quick to rant about companies when their service lets us down, but I think it's also important to be just as quick to praise them when they get things right. When we moved, I had to decide which company to use for broadband provision. In our old house, we had Telewest for phone and broadband (only because our landlord already had it set up and it was too much hassle to change), but I didn't really want to continue with them. I knew that the new house had a BT phone line, and that the nearest exchange was ADSL-enabled, so that left a pretty large choice of ADSL providers.
I did quite a bit of research, and also used the invaluable ADSLGuide to get the inside information from users about speed, reliability and customer service. That knocked out quite a few companies to start with. I was tempted for a while to go with TalkTalk, but their waiting times for connection are pretty horrendous, and for an internet junkie like me, being without broadband at home for a month or more would be like asking me to do without oxygen.
So after a lot of thought, I decided to go with Zen Internet. They aren't the cheapest provider around, but they have good 8Mb plans, dedicated Mac support and rolling one-month contracts, so that you're never stuck in a contract you want to get out of. I called them about a week before we moved house, and was amazed when I plugged my router in on the day we moved in and found that we were connected. I didn't actually get enough time to do anything with the connection for several days, but I was really impressed by that. So if you're thinking about getting a new broadband provider, I can heartily recommend them. My brother is also with Zen, and he has been very happy with them too. Needless to say, I've got no connection with the company, other than being a contented customer.