Super Mario Land 2 is pretty likely to hit the shop sooner or later, and I recommend it to anyone who missed it, but I already played it to death when I was a kid. I'm more interested in gems I missed, such as Donkey Kong, and I'm not convinced there are many of those. The only game I already own that I'm sure I'd buy again is the One True Tetris, but something tells me it's not likely to be made available. :-\
Edit: I take that back. I might buy Motocross Maniacs, too, just for an occasional fix.