I'm personally tired of buying the poor quality £19.99 universal power adapters for my laptop so decided to invest in a decent quality one from Maplins. It's an Innergie mCube Lite with 3 year warranty, Lifetime replacement tips, powerful USB socket (even charges my iPad), and compared to the cheaper ones, it's very compact and light. Anyone with any experience of the cheap £19.99 versions will agree that they are renowned for their dodgey wires and tips that keep breaking. Yes the Innergie one is more expensive but the benefits make it worth it!
Direct link here - http://www.maplin.co.uk/mcube-lite-notebook-adaptor-389045