Reasonable on 21 March 2009
Top would probably be Grim Fandango - one of the best games ever but of course once you've played it you know the solution to every puzzle.
Portal be another title. Once you've beat it you know all the puzzles, etc.
ICO and SOTC would be another two similar titles I suppose.
I've replayed them all more than once though, just to relive the experience they delivered.
Try to be reasonable... its easier than you think...
