you have got some good leads from the previous postings the only thing i would add is to get all the components from the same source if possible so at least if you have any queries/problems you won't get shunted between different suppliers.
let us know how you get on as my son is pestering me for an upgrade.
Tested so they are working together. As suggested by "Dumble452" novatech do good deal click here. watford also go good deal as well you can search for motherboard kit, e.g. click here
As for front usb port, if you have to have them, you do can still use your old case if you have a 5.25" bay or 3.5" bay on front free (you need to take off cover plate of course). You just need to get internal usb hub to fit it, for example 4 ports 3.5" one cost £6.1 click here, 4 ports usb and two port firewire costs £11 click here (if motherboard support firewire).
If you pay more, you can get one bay with usb, firewire, earphone, mic, line in etc. A few big sound card makers do them, cannot remember which ones.
You have all been very helpful and I have plenty to look through. On the face of it Novatech look a likely candidate. Much appreciated.
TomJerry: I could go for barebone system - I have perfectly good video and sound cards, 2 HDDs with ample capacity, DVD and CD-RW. All these components suit my needs fine. I could just do with a bit more 'ooomph'!
Thanks also for the advice re front/rear USB, hubs etc - I have learned something today!