I've been looking on and off for a while, but do want one.

I don't want it to be too expensive
It needs to have UK maps, speed camera detection (most seem to have that anyway). Also, I don't have a CD player/MP3 player in my car so having an MP3 player built in to the Sav Nav would be great. If it has that feature then I'd also need traffic reports on it as my radio won't be on.

Anyone got any suggestions?

Note: If I can just plug in a memory stick, MP3 player stick into it, or put music on the SD card and be able to play it though it that would be fine.

I have a budget Garmin Nuvi.
http://www.newegg.com/Product/Product.aspx?Item=N82E16858108052
Pretty nice little device, but not all the features you want (like speed camera detection) I don't think you're going to get all the features you want for less than $400 equivalence.

Sounds like what you want is this:
http://www.pocket-lint.co.uk/news/news.phtml/6439/7463/garmin-nuvi-370-670-worldwide.phtml
http://www.newegg.com/Product/Product.aspx?Item=N82E16858108045

Have to admit, I'm really confused why they can't just whack on, or just allow you to plug in an mp3 player. Can't cost more than £10-20, yet it seems you have to pay about another £100 extra.

I was just looking at the TomTom Go 520, more expensive that I'd like to pay, but you can have traffic updates and listen to your iPod through it. However, another site said that you cannot do these at the same time, because they use the same port. What genius decided that would be good?

I don't want to fork out money for a new radio/cd/mp3 player in my car plus a sat nav. That's going to be £300.

Sorry for the rant but poor product design is something I can't stand. Why do they leave gaps in the market? It's in their interests to fill it! I would have bought it if it had 2 ports instead of 1.

I honestly don't feel like I'm asking for a lot. I don't see why an Mp3 built into a sat nav should be much more expensive than an mp3 player.

I got a Tomtom 300 on Ebay that does all I want. It can play mp3s too.

They have speed camera maps - not detectors though!