I've added a Nikon D300 with a Nikkor AF-S DX 18-200mm zoom (27-300mm equivalent on a 35mm camera) to my arsenal. It was a major, and expensive, step to get back into SLR photography after over a decade of sticking to digital point-and-shoot cameras. The D300 is a big, heavy beast, but a DSLR has much greater potential creative control and image quality. It'll be fun going through the manual and playing around with all the menus and functions!
I have several old 35mm film Nikons and a bunch of Nikkor lenses that are basically worthless now -- no trade-in value at all, though I paid several thousand dollars for the gear (in mid-1970s to early 1980s dollars!). While these old, magnificent, optics can still be used on high-end digital Nikons like the D300, it's a bit of a hassle, and when you have a super-zoom that pretty much covers the range of four or five of the old lenses....
But I guess it all worked out -- though I've never been a professional photographer, I made enough money using that old equipment to pay for it, and I hope to do the same with the big investment in the D300 and lens...

The "worthless" collection...

The hefty new D300.