Yes Pete, there are either Canonians or Nikonians in the world of photography, unless you want a real
camera and buy something like a Leica or Hasselblad.
Canon tends to have more gadgets and sytems, wereas Nikon's stress is on quality lenses but lesser technology. The disadvantage is, all those gadgets are getting into your way, when taking a photo, rather than supporting you. Most of these gadgtes aren't so useful anyway.
You guessed right, Kroisos, I'm a Nikon man rather than a Canon supporter.
I own several cameras, photography is another hobby of mine and all the old analogue cameras I must say are still better than the modern digital ones. I have a Nikon F2, an old 1930ies Leica and my best is a Rolleiflex Twin lens reflex camera beeing still better than my new Nikon D5000 entry level DSLR. What I want to say is this:
I get the impression, that the new digital technology is less reliable, longlasting and stable than the old analogue cameras. If you open an 800€ camera like my Nikon D5000 you get shocked! It's all plastic inside!!
Thus I would never recommend you to buy a used digital camera. (unless you don't want to spend 5000€ on a D3 or so)
I bought my D5000 kit with two lenses (18-55mm and 55-200mm) for 750€ which is a solution I'm very content with. For macro shots I have made good experince with inexpensive (30-50€) close-up lenses/filters ( 5 and 10 dpt, made by "B+W") that are applied like a filter. They are screwed to the end of my 18mm lens. A real macro lens costs easily 200-300 € alone.
If you have only 500€ to spend, it would be better to save money till you are able to buy a good system of let's say 600-700€ than to waste your 500 on a used camera (without warranty!) that could give up the ghost soon after you bought it. To spend 150€ more is not that impossible to achieve but you'd be on the safe side.
To give you some information about the camara, the D5000 is an entry level camera that makes good pictures and is about on par with the older and slighty more expensive D90. Contrary to the D90 the D5000 has a flipable display that is very practical to use.
Regards,