PS3 controller requires a bit more additional setup, Xbox 360 seems to be the most accepted. Personal preference on which you prefer really. I go for a wired 360 controller.
http://www.amazon.co.uk/PowerA-Air-F.../dp/B005761E70
One of the best third party controllers I've played with. Seems the popularity got the better of it and thus increased the price given I got it for £20 at Christmas.
Standard 360 wired controllers could be had for around the £20ish mark now I would assume.