Wishbone: You seem to have missed the point of the discussion. We're not talking about games in general, but the games sold by GOG. Since one of their major selling points is that the games have been updated, and are guaranteed to work on modern OS's (in this case XP and Vista), what we're wondering (the forward compatibility crowd) is whether GOG will continue to support the games on future platforms. Or whether, a few years down the line, we will again be unable to play these fantastic games because we've switched to Windows 7.
Conversely, the backward compatibility crowd are interested in also having the original, unaltered games available. Many old games have had various mods, updated engines, etc. made for them, things that may not work on the new updated versions sold by GOG.
All in all, we're all interested in getting as much out of these old games as possible.