So, I've got Heaven and Hell and Aletheia, and I've got to say I find the model that Abstract Nova have used for those two games completely intriguing.
Specifically, both games are designed almost like "campaigns with rules" rather than stand-alone RPGs: they both assume that the game is going to revolve around a particular overarching plot, and include the same NPCs, organisations, and locations (especially Heaven & Hell); there's a clear starting point, fairly major pointers to where the endpoint is likely to be, and whilst getting from A to B is going to be different for each campaign exploring the overarching plot and discovering the "truth" behind the games' respective settings is almost always going to be a big deal.
(Heaven and Hell, for example, assumes that the characters are going to be locals of the town which the game is based around who get drawn into investigating its occult mysteries, and provides lots of details on the town and its inhabitants. Aletheia is even more tightly-defined, and begins with the PCs recruited into a secret society which has had its entire previous membership - aside from the butler - disappear.)
I've got to say, I kind of like that model. It doesn't feel quite as restrictive as it should, somehow - perhaps because the hardwired-in plots and settings don't seem as restrictive, and in particular don't make any assumptions as to how the PCs actually react to the settings and situations in question. And I have enough setting/plot-agnostic RPGs already to cover pretty much any genre I'd want to run a game in. Additionally, the "truth" in both of those games seems fairly easy to quietly replace with your own truth if you don't like them.
What other RPGs are there which follow this model?