I love Ogre Battle. It's a bit better for PSX (which is also nearly impossible to find) because you can save in the middle of a campaign/level. Sure, it doesn't seem like much in the first few levels, but wait until you get closer to the end. The awesomeness of it is the troop building and choosing your characters paths. Also, different things happen if you're able to find some of the hidden characters. A friend of mine gave me an Ogre Battle cart as payment for some artwork, so I'm REALLY lucky:)

Lately, I've been playing Rushing Beat Asyura, the Japanese (read: unmangled) version of Peace Keepers. The beat 'em ups from Jaleco were one series Rival Turf was Rushing Beat, Brawl Brothers (the one that got me hooked) was Rushing Beat Ran, and Peace Keepers/RBA was the 3rd. Despite the fact that all 3 were translated by the same company, they were translated with total disregard for continuity. How badly, you ask? So badly that the characters names change with every game. As much as I love the Final Fight characters, I think that Rushing Beat Ran and Asyura are much better (and a lot less cheap).

I remember renting Zombie ate my Neighbors and liking it a little. It's like Alien Syndrome with spunk and complex mazes.