This is a personal opinion (obviously) but I would look at a
second hand dslr, simply because they are soo cheap now, and they won't lose any more value so you will get the little money you spend back in future if you decide you want to upgrade to something modern, whereas if you buy something modern now, you will lose money when you come to sell in future.
Some suggestions from myself..
Nikon D200.. £90.. CCD sensor, old technology now but considered by many to be the best sensor for skin tones. Poor low light performance. Professional control layout.
Nikon D90.. £100.. More modern CMOS sensor, has 'beginner' auto modes, great colour rendition, all around nice camera. My first dslr. Takes video.
Nikon D300s.. £130.. CMOS sensor, professional control layout, takes video, weather sealed.
Nikon D700.. £300.. Full frame, professional camera, considered by many to be the pinnacle of Nikon cameras for it's beautiful images it produces, pretty much a one of a kind, excellent low light performance, aptly named 'the legend'.
These are rough prices going off of
MPB, In my opinion none will lose any more value as they are pretty much rock bottom and appear to be increasing in value recently.