This will probably get voted cold immediately, but this may be of use to those who are close to buying a Sat Nav. Buy either the Navman S50 or S70 and get a Traffic Cradle worth £54.95 free. I have done a quick check and the Sat Nav themselves seem well priced.
I bought the S70 a couple of months ago and this would have been a nice freebie.
This isn't something that is very easy to spot on Amazon and I don't think you are made aware of the offer if you take the stand alone unit through to check out.
Might be of use.