Keyflower. The core game play mechanic is very simple in that essentially everything is just bidding meeples that it is very easy to teach, but there is so much to consider, a ton of interaction, meaningful cost/benefit decisions, and so many ways to build up without being too much of a point salad. The game itself is very attractive on the table without being garish, and it can be kind of ruthless. It also scales beautifully, I have played it with 2 players and I have played it with 6 and its great everywhere in between. The iconography is clear and simple, the expansions are both great (although I prefer the Merchants for low player count and the Farmers for high).

I am big fan of the digital version of Race for the Galaxy (and the in person version) mainly due to the speed at which it can be played and not having to shuffle constantly.