Have you seen that *rgos (and probably elsewhere) have the Start 60 (that's the one with the SIX INCH SCREEN) available for a penny under £130? Get the Traffic Receiver car charger for about £20 (ensure the connector is suitable for the Start 60 model!!) and you'll have something like a built in SatNav and updated traffic info.
You can also get a beanbag dashboard holder that has good reviews and avoids leaving any tell tale ring on windscreen.
Comes with free UK/ROI and Europe "lifetime" (?) maps upgrade. Offer ends in March 2013
Disclaimer - I DON'T have anything to do with TomTom, just thought it was a good cheap combination.
It's maybe not the best, but the price makes it worth considerng.