Oregon 300
I have a Oregon 300 will Garmin OS discoverer National Park maps, you get route able garmin NT 2009 maps for the UK, OS map 1:250k for UK when you zoom out and OS map 1:50k of all the National Parks in the UK which is also route able, all on the same micro sd card, i think you can buy this for about £80 ?. There have been allot of firmware updates with the Oregon which improved the visual look of the OS maps and lots of new features, Garmin say they will be bringing out OS maps for the whole country, like Satmap and when they do, it will be a better unit than the Satmap for the simple reason that it does everything, car, bike, walk and mc use, just use external power cable for a brighter screen.
I use mine everyday, today I`m on my MTb in Bracknell forest, fits nicely on the handle bar stem, its got camera warnings for the journey there and when I go to te US in October, I`ve topo US to use. Garmin just need to get the OS map coverage sorted and it will be the best IMHO. I will post some pics later if your interested. You can get a 300 with the maps I have for £317 and the car kit cost about £30. I use rechargeable Nimh batteries which with full back lighting on, last about 8 hours. The back lighting isn't the best, but having looked at the satmap, neither`s that, in bright daylight either, but garmin backup and build quality is better. Touch screen is very good and quick, but re-draw is a bit slow when you zoom out, whereas the satmap is much quicker.
The garmin Oregon is the best all-rounder, satmap is no good for road routing although if your prepared to mark multiple way points, it will draw straight lines to each one.
P.S. do not buy the Colorado, its crap, novel toggle wheel gets very tedious after about 5 minutes.