So this is the O2 love-in forum!
Sorry to dampen your enthusiasm but I moved from BT to O2 in July 09, went fine and started off ok but my wireless Lan has never worked well since I moved. I think the Thompson routers are to blame. I keep losing the wireless connection many times a day. O2 support have suggested a few things to remedy it but it hasn't improved. Yesterday the ysent a replacement router (Another Thompson but this time a bigger one with 2 aerials. Installed ok but still got the same rubbish wireless connection. The signal strength shows as excellent or very good on our 3 laptops at home. Then the new router decided to go faulty and finally reset it self minus any WPA security. I ended up putting the older router back in, Tried contacting O2 3 times on the phone and via their chat window without success. Sent them loads of emails which they've not replied to.
And to top all this in the last 3 weeks I'm seeing mega problems accessing many of the popular websites like BBC, GMX mail, google maps and so on. They asked me to enter some manual DNS addresses which I did but haven't helped.
So I'm beginning to get somewhat dis-illusioned with O2 broadband after 4 months of problems and I've given them 7 days to fix my problems or I'll be going back to BT despite the higher price charged by BT.
I must say their helpdesk are courteous and helpful and they try hard. But they are becoming harder to contact and have not fixed these continuous problems. So beware, my guess is they've overstretched their resources with 600,000 new customers.
Steve