O2 relaunched all their tariffs yesterday dropping "unlimited data", but what has replaced it looks pretty good:
The O2 simplicity sim for smart phones now offers 300 minutes, unlimited texts, 500MB data and unlimited wifi (this is a new addition for the smartphone sim) for £15 per month on a 12 month contract. Add in the current offer of topcashback of £100 on tariffs on £15 or more and this works out to just £6.66 per month over the year! The iphone sim is the same price.
Don't want data? Then 300 mins + unlimited texts + unlimited o2 calls or landline calls is £10 per month, but with £50 cashback works out to just £5.83 per month over the year!
Have a blackberry? Then there's a tariff for you that also offers 300 mins + unlimited texts + unlimited blackberry data + unlimited wifi for £10 per month, after £50 cashback = £5.83 per month.
(I've modified the title to reflect that the data on the mentioned smart phone tariff is 500MB - 1GB only applies to a far more expensive tariff, which O2 confusingly/misleading listed as "up to 1GB" above all the tariffs)