Check out this website:
Compare GPS Prices
Should find yourself one on there! The tomtom510 deal with free traffic from Dixons looks good.
I've had the original tomtom one for ages and I bought the full European maps for about £80 downloaded directly from
TomTom, portable GPS car navigation systems.
I've also subscribed to the tomtom traffic and speedcameras service via my mobile phone GPRS connection using bluetooth, but it's not that great.
Look on
TomTom, portable GPS car navigation systems for the differences between the one, 510, 710 and 910 - it can get a bit confusing.
Also look on
Pocket GPS World for great advice and review.
You could also consider the Garmin range:
www.garmin.co.uk as they are pretty good.
If you want any advice just shout - I've been messing around with tomtoms for ages!