Bought my first SLR in 1977(ish), a Nikon FE and gradually built up my equipment bag with a MD12 motor drive, 28mm, 135mm and 200mm Nikkor lenses and finally a 600mm Sigma Cat lens and also a F3. I dipped my toe in the digital arena a couple of years ago with a Lumix DMC-FZ18 which is a Bridge (type) camera. I find this an excellent piece of kit, the 18X zoom lens being the equivalent of 28-502mm but the images do fall apart a bit towards the upper areas of magnification.
Last year I took the plunge and went "full" digital with the new D7000 and although in some respects the considerably cheaper D5100 was my first choice, I went for the D7000 bacause it works in terms of fit and metering with all my old lenses and therefore saved me a small fortune by not having to buy all new. The lack of Autofocus on the old lenses isn't a problem for me as if using a telephoto I'll probably have it set to infinity anyway.
The only lens I haven't tried yet is the big Sigma otherwise I'm very pleased with every aspect of the camera even though I may not use all its features. The Lumix is a lot more compact and lighter than the Nikon, as you might expect, and is inconspicuous enough to not attract the wrong kind of attention.