What game are you likely to give to others?
Different strokes for different folks. I can’t say there’s one game I’d give universally. D&D is a solid choice for many fantasy fans, but even then it may not be the best choice. I’d love to give Dungeon World for its simplicity. Apocalypse World for those who may not be into fantasy, but still would like the simpler system. Shadowrun is great and oozes an amazing theme. G.U.R.P.S is a gateway drug for many, with it’s staggering amount of content past the core rulebook.
When it comes down to what I actually have given to people, there’s only 1 (two if you count editions.) I’ve only ever given the HDL System and Paragon: HDL 2nd Edition from Tremorworks, I publishing company I cofounded back in 2006.