O/T Mobile phone contract advice please

My old contract with T-Mobile has been up for a couple of months and I've just got round to looking for a new one, so I spent a couple of hours looking at deals tonight, phew ! it's a proper minefield out there innit. Can anyone offer any advice, what networks are offering the best deals for around £20 - £25 a month, I don't need a fancy phone with GPS, free Mp3 downloads or mobile internet just something to speak to people on is fine. What are you guys using ? What would you recommend ? Your advice please gentlemen 
