It's not always just the iron, it's the technique you use also. Flux can be a massive benefit in soldering.
I posted a video online to help some people with soldering:
https://www.youtube.com/watch?v=Qj-9zTSAUTg
In that video I was using this soldering iron:
http://www.maplin.co.uk/p/antex-25w-...ing-iron-fr12n
I have since upgraded my iron to this, as the 25w is fine for indoors, but if you are at a cold outdoor race meeting, it doesn't get hot enough:
http://www.pmtech.co.uk/consumables/...g-station.html