Just because a game isn't on the shelves, doesn't mean its actually OoP.
I love that game, and its still in print as of 2006! (Not much new stuff, though.)
http://www.heliograph.com/
Is Battletech still around?
See here!
http://www.classicbattletech.com/
Classic Traveller (as well as Twilight 2000) is indeed available as a reprint from Far Futures Enterprises (
http://paizo.com/store/brand/traveller/classicTraveller ).
I count myself as one who misses Melee/Wizard/TfT/In the Labyrinth, though- a set of simple fantasy combat games that morphed into among the best ever simple FRPGs.
Mayfair Games' Underground is another fave of mine that goes in and out of print.
Meanwhile, what I really miss are the simple but fun board/wargames that were available from Microgames (though Ogre/G.E.V. is still available from SJG in a variety of forms), TSR, GDW, Thom Wham etc. Cheapass games' product line is a worthy successor to those companies (and I own many), but I still miss playing Saga, Hot Zone, Helltank, and so many others. (I still own many of them, but you know how it is- parts go missing, hard to find opponents...)
I miss some of the nontraditional combat games too, like the diceless POV WWI/WWII air combat game Ace of Aces (
http://maverick.brainiac.com/aoa/aoa1.html ) and its fantasy counterpart, Lost Worlds (which goes in and out of print- see
http://www.flyingbuffalo.com/lostw.shtml ).
