One thing you'll have to decide on is what your first priority is with regards to your requirements. There is no product out on the market that is a leader in both segments as the different companies who specialise in Navigation devices add cameras as a second thought and those that specialise in camera detection have added navigators to bump up their product ranges.
When I was looking my first priority was camera detection so went with a Road Angel Navigator, others may have gone with Origin/Pogo for the same reason as these are the 2 recognised market leaders. Those that go for TomTom or Garmin want good navigators but a sacrifice is definitely made on the opposing feature of camera locations.
Around your budget situation with my needs I'd go for a Road Angel 7000 but this is just over £200 as I've always used Road Angel and feel their database to be one of the most up to date. If I wanted a good navigator I'd go for a Sony NV-U82 which is £230 from Play.com:
http://www.play.com/Product.aspx?r=E...25&source=9593
I understand the money is slightly more but after using TomTom, Garmin and Navigon mapping I found the Navigon to be superior in detail however input slightly longer but this is far better then getting lost. That added to the 4.8inch screen it's hard to beat. I believe there is a thread on the Sony Nav's here saying how good they are.
If you do go for one of the better navigators just don't expect the best performance from the camera side of it. I ran a friends Garmin 670 and my old TomTom Go alongside my RA Nav9000 and found the others to be no where as near reliable as my unit on the camera side of it (TomTom worst, Garmin had most sites but missed out on both fixed and mobile vans). However on the flipside my nav's mapping is not as good all the time as the Garmin was (unless you avoid motorways where the Garmin fails miserably).
Anyway I'll no longer ramble on as I've done plenty of that above.