Are you including the Wolf RPG games?

Ao Oni was pretty good, but I think some of the visuals could have been better.

I really like Mad Father; but that's Wolf RPG Maker, not RPGMaker brand.

i'm gonna go with Misao. Freaked the hell out of me.

For me, flat out going to say Ib.

My favorite would have to be Ao Oni because some moments it scared the crap out of me LOL xD and Mad Father because it was such an awesome game

Probably MLP RPG: Fighting the Unknown. It was the first RPGMaker game I played, and is pretty awesome :3

Ib ib ib ib ib ib ib ib ib.

Or Ao Oni because of the fangames.

It's definitely Ib! Mad Father, Ao Oni, Misao, and The Witch's House were all wonderful games, but I need a hero, someone to restore my faith in humanity. Ib was the only one who had someone admirable who saved the day. You know who I speak of. I guess the nameless Heroine from Misao could also count, but something about her (i.e. when she lost her contact) was off. Maybe I'm too character-oriented...