With your lower budget I would go with an AMD set up. A socket 754 and an AMD64 2800. No less than 512MB RAM. Onboard sound will do OK, it's better than it used to be. DVD burners are fairly cheap these days.
IDE is not dead, but SATA drives are faster and more efficient than IDE. Optical drives are still IDE, there are some SATA drive but are costly.
For a vid card I wouldn't go under an ATi 9600 or nVidia 5500. There are cheaper cards, but not worth getting unless you are really strapped for cash.
I'm in the US so can't quote you any prices or where to purchase them. Jordan, our UK specialist should pop in soon

. You might be able to afford a socet 939 system, much better upgrade path. But again, Jordan or another UK member would be able to get you some prices or where to look.