The FD 35-105/3.5 constant aperture lens is one of the legendary ones, but demand makes it costly.

The Tamron SP 35-105/2.8 constant aperture lens, which I have, is a newer design and is really a fine zoom. It's sharp as a tack and has interchangeable mounts, so you can use it on your Minolta (and justify the price a little more). It does show some pincushion/barrel distortion at the extremes of the zoom range, but all tele-wide zooms show this. The constant aperture feature makes it great for non-TTL auto flash use or if you use a handheld meter. There are a couple of later versions of this lens with wider zoom ranges, but I think the 35-105 is the best choice, because as the zoom range increases, there are more compromises between sharpness and distortion (until you get to those pro cine/video lenses with a 10x zoom range that cost over $100,000).