I have a very limited group of games: Civ IV BtS, M2TW (I don't play the battles and just empire build), Warlock I, ramping up/running pnp D&D. That's it. There's others that I will play, Age of Wonders 3 & Sovereignty: Crown of Kings got a lot of my time in the last four months or so. And if the mood ever strikes, I would go back to Hearts of Iron 2 in a heartbeat. I want to learn something Ageod, but the system escapes me. The maps are simply gorgeous. That's about the limit for me. I would take the time to learn something involved, but, it would most likely have to be something MP.
A thought for those who express too much effort/too little time, specifically board games and flight sim configurers, when the mood hits, take advantage of it. Go into it knowing you are only going to accomplish the set up. Or learning one point of the rules that has you a little stuck so the next time you get back to the board, you can move forward. Just my .02