Thanks DW. What sort of zoom lens would be good? Are you referring to a kit lens type?
Depends on what you're hoping to do in the long run. If this is just a passing phase and not something that you are thinking of taking seriously then sure, a "kit" lens would be ideal. Maybe something that runs between 35 to 200, or maybe two lenses that cover the space between the 20's and up thru 300 at the top. You should be able to pick one or two of these lenses for around $600 to $800, maybe less depending upon the lens.
But if you're thinking of taking this serious, and you certainly have a serious camera, then buy the very best lens you can afford. Lenses like the 24-70mm F/2.8 and the 70-200mm F/2.8 are the best of the best and you can't go wrong with them. But again, these are very expensive lenses, not because the whole package is that much better than cheaper lenses, rather it's the little things that make these lenses so great. They lack small things like corner sharpness and barrel/pin-cushion aberrations, most of which can be adjusted in Photoshop/Lightroom, so you only consider these lenses if you have deep pockets or are serious about your photography. Otherwise, they're not worth the extra money they cost and you'll do just fine with the lower priced lenses.