Cities XL really depends on how bad you want something like SimCity that's better looking than 4 and not the new one.
It's a game (not even a series, each "year" was just an expansion + major patch) that's put two developers out of business.
I think they finally got rid of the memory leak though. The original developer never patched it out of 2009 and then like vanished into the night or whatever so they gave everyone who owned it on Steam like 90% off 2010 when it came out. :lol
spoiler (click to show/hide)
2010 still had a huge memory leak, just not one that'd kill the game after an hour.