With regard to the "halfway types" I'd recommend the Sony NEX-5 (or NEX-3 if you're on a budget). You get the same APS-C sensor as a digital SLR and great performance in a small package. There's limited choice of lenses made especially for it (3 at the moment, but another 7 on the way) but with adapters you can fit anything you like.
Its £399 at Jessops: http://www.jessops.com/online.store/pro ... /show.html
I bought one before Christmas and have been very impressed (standard 18-55 lens):
These were taken with an old Canon FD lens (£20) via an adapter (£18):
It also has an excellent movie mode - shoots full HD with stereo sound and silent autofocus (absent on most DSLR's).
With regard to a proper DSLR, then the Canon 550D (or 500D if you're on a budget) is a good choice. The 60D is also an excellent camera, but probably not worth the extra outlay if you're new to photography.