Talislanta is still in print. It's probably going to be _out_ of print soon, but it's been moving along quietly. You can pick up the 5th Ed books on Amazon, as well as buy the older edition pdfs here: http://www.rpgnow.com/index.php?filters=0_0_10123
Marvel FASERIP (had a blast rationalizing random powers)
Millennium's End (I just loved the overlay system)
DC Heroes (once you figured out the system you could build just about anything)
My favorite out-of-print games right now are probably TSR's Marvel Superheroes, Basic D&D, and White Wolf's Street Fighter. I don't actually miss them because we still play them regularly
The consensus on the internet seems to be that Street Fighter was broken, but I dunno. I actually think that's something of a myth. We played it weekly (sometimes twice a week) for 7 years straight (3 full-length, multi-year campaigns), and we had no real problems. Maybe because we stuck to the core book and Secrets of the Shadoloo? Anyway, I think the core rules for the game are a lot more robust than many people give them credit for.
Marvel super heroes adventure game which used the SAGA game rules. Also the Street fighter rpg by white wolf. I enjoyed that when I was new to the world of rpg's. But sadly I lost my copy of the book. Oh and the TNMT rpg.