If you want to change the color, or have dark windows as BK suggests, stay away from vinyl windows, as the dark paint will cause the vinyl to absorb more heat, which will cause the vinyl to warp.
The first question is where will the windows go? If they are high (clerestory), out of the way (closet in pre war homes), you can sive a little on the interior finish.
The best looking will be a wood clad window (interior = wood; exterior = cladding - vinyl, aluminum, fiberglass). If you live close to the ocean, you will probably want vinyl clad or fiberglass clad. If you are inland, aluminum clad is preferred. The aluminum is more rigid and less likely to chip or crack. However, changing colors is tough down the road, and salt can be tough on aluminum. Vinyl is cheap to produce, easier to produce as sealed (they just "weld" the seams together) for energy efficiency, but can not be painted dark on the exterior (although they are making some dark vinyl extrusions), and they look like they are vinyl. Fiberglass can be painted, but it is more expensive to produce, and the technology is newer.
On the interior, the wood can be composite (MDF), finger jointed short runs (individual pieces 4 - 12 inches), or laminate wood. The later is preferable, as there are less glue joints to fail, and more importantly, to "pop" through the paint - a common problem with finger jointing). The composites are a little rough for my tastes.
The creme de la creme of the window world in North America is Loewen. They use clear fir laminations, have great hardware, and the aluminum cladding is joined exceptionally tight.
Milgard makes an impressive fiberglass window, and I believe that they have a sash replacement system (rlacing the windows without taking out the sash).
If your windows are the classic pre-war wooden windows, the best bet is to just repair them - they will look better that way.
