Basically what I need it to do is be fast, broadband compatible and be able to download songs and burn onto cd's and of course surf the net
Any modern computer will do that without problems. The main consideration when it comes to how much you spend is games - modern games still require quite a high-spec PC.
ive heard about Dell, ive got a currys and pc world etc near to me so any advice on this wd be great,
Avoid all of them. You'll get a better PC from a specialist - personally I think Mesh are pretty good.
As for broadband, if you search on this forum, you'll find several threads discussing providers. I've used Pipex for the last three years and think they're very good.