I would say don't bother if you aren't going to overclock, the stock cooler isn't too bad actually. If you are going to be overclocking, then yes, most definetly, a bigger better cooler will help a lot.
As for which one, well there are many to choose from. I personally use a Noctua NH-U12P, this is quite expensive though. I noticed the OCZ Vendetta 2 is on 'this week only' for £25 at OcUK, that looks like a decent solution.
The Scyth Infinity is a good one too, and if you don't want to spend very much, Arctic Cooling Freezer 64 Pro has always been the sub £20 weapon of choice.
As for which one, well there are many to choose from. I personally use a Noctua NH-U12P, this is quite expensive though. I noticed the OCZ Vendetta 2 is on 'this week only' for £25 at OcUK, that looks like a decent solution.
The Scyth Infinity is a good one too, and if you don't want to spend very much, Arctic Cooling Freezer 64 Pro has always been the sub £20 weapon of choice.