Is it important for you, if the game makes the decisions about the development of the character or the player? Because that is the main difference between the definitions of Torillian and me.

The mechanic is not so important in my opinion. Hearts, experience, whatever. But in Zelda the hearts do not much to develop your character. The other stuff is completely dependent on your progress in the game. except Zelda 2, it is a RPG.

I suppose for me it's a game where the player has a great deal of control in how to improve your base character(s). I don't think it has to strictly be stat based (I still count Deus Ex Human Revolution as an FPS/RPG) but it shouldn't be solely tied to in-game progress and there should be multiple elements you can improve/develop as you progress. For instance, the hearts in Zelda are for the most part, a result of game progression, or the in original Metal gear Solid where your health increases after defeating each boss; I don't count either of these as RPGs.

However, I also feel that storytelling should play a bigger part in defining what makes an RPG. The ability to influence the storyline is usually associated with adventure games, but to me this also makes a significant portion of what an RPG should encompass; shaping your character not only in battle stats, but also in character/personality development. In games with a party system, this should include inter-party relationships.

IMO combining both elements (stat increases and character development) is what makes a truly great RPG.

"In this article the author Karl Koebke tries to give a definition, what a RPG is. Let's take a look. The definition he comes up is:

1.Main focus of the game must be (largely) persistent Player controlled characters with base stats that define their attributes and which can be increased over time, e.g. strength and agility.
2. There must be some means for the player to increase the base stats of these characters over time by completing objectives which is usually, but not always, called “experience”."

So Metroid isn't an RPG but Castlevania Dawn of Sorrow and GTA: San Andreas are?

I'm pretty all-inclusive in my definition of an RPG. The genre was founded on two principles: stats and player choice (I'm basing this off of D&D, the first "RPG"). As such, games built around at least one of those two concepts can be considered RPGs, but I heavily stress the "built around" part. Stats and/or player choice must be an integral part of the game, not ancillary, and must be used directly. I do not count "invisible stats" or health bars. The game also must allow for stat management in some form.
Now, when I look at The Walking Dead or Heavy Rain, I see RPGs in the player choice sense. Character development is interactive, and is pretty much the games' key element. However, they fall in line with traditional adventure games in some ways so I can, by my definition, consider them to be adventure/RPG hybrids.

I am largely in disagreement with just about everyone on this one. For me, an RPG is a "ROLE PLAYING GAME", which to me means assuming a PRE-DETERMINED ROLE, such as when an actor plays a role.

What most consider an RPG I consider more creating your own role, which I guess should be titled RCG - "ROLE CREATING GAME". This means that JRPGS to me are actually the true RPG's.

A few years ago, I would've said that the game making the decisions for development were the most important to me. This was mainly due to me being very indecisive when it comes to make choices in games and due to RPG's being better story-wise when the development is out of the player's hands. I was completely content with playing an RPG, leveling up and getting some predetermined stat boost or new ability. 

AFter playing games like Dragon Age: Origins, Demon's Souls, Dragon's Dogma, and Kingdoms of Amalur, I'm more or less 50/50. Both types of development fit my criteria of what an RPG is.

Experience points or something analogue, and being turn-based or semi-turn-based. A degree of customization is important too but not to the point of defining the genre.

That's for me at least. So I don't consider Zelda, Monster Hunter, Mass Effect, Elder Scrolls etc. to be RPGs. Dragon Age and FFXII would make it though, since that's what I'd consider to be semi-turn-based. 

I don't remember GTA: San Andreas having any base stats, you leveled up your use of different weapons by using them, which is certainly RPG-like and has seen use in games like Oblivion, but since the character himself does not have base stats that determine his attributes and increase over the course of the game I wouldn't consider it an RPG.  I'd have to look into Dawn of Sorrow, but no Idon't consider Metroid to be an RPG, and I'd be somewhat surprised if anyone does.

When most people say "RPG" - including Mr. Koebke - they are referring to a subset of the strategy genre.

Health points, experience, leveling, individual attack stats - those are strategy game holdovers predating Dungeons and Dragon by quite some time. Ditto being turn-based, though that's a more obviously strategy game idea.

More appropriately, "RPG" is not a genre, it is a narrative mode. Most games called RPGs, including the likes of EarthBound and Final Fantasy and Dragon Quest and Knights of the Old Republic, are highly specialized strategy games with an RPG storytelling mode. Mass Effect is an action game with an RPG storytelling mode and strategy-based base stat management. Ditto the Elder Scrolls series.