There wouldn't be much benefit, if your current router is serving you well and it supports ADSL2+ (up to 24 Meg speed); then there is no real reason to upgrade.
Unless of course you need advanced features, better wireless standard (wireless N for example) or more switch/wired capacity.
Keep in mind, most laptops and wireless devices are still manufactured to 'G' standard @ 54 Mbps - so any of your old kit will not really benefit.
As far as I'm aware, BT require you to take out a new contract in order to qualify for a new router and besides, it wouldn't be very good (Home Hubs are only average and not worth the 12-18 month contract).
You could go to your local store, aim for a Netgear branded ADSL2/2+ modem / router (don't forget the modem part) and set that up. You could see it as future proofing I guess and may benefit from better stability, speed - especially if you're on a long line.
Let me know if you have any more questions, feel free to add us to MSN or e-mail directly and I'll be happy to advise you further.
All the best,
Ryan
