27dnast is right... ish. IM won't last that long for you in a one game collection. However, it will rock while it's there. I love IM. It's a fantastic game, but it needs other games around it to keep it interesting long term. Long games are not a problem.
Spider-Man suffers from your same issue LOTR does. The games can be very long. Once you get the shots down, competition can be a long endeavor. It's more of a solo game.
I've never liked IJ, so that obviously taints my opinion of it.
With only one spot, you just have to commit to owning everything one at a time. Rotate out once they get boring. That also gives you the opportunity to bring in classics for a visit. My current classics obsession is Stars, but there are dozens of great games from the 70s and 80s that are worthy of a few months visit.