You never disappoint!

Loved dark/demon's souls. That will always be my number 1 RPG.

Dark Souls for me. Mass effect a little behind in second place. I haven't played Lost odyssey... maybe can be my #1

Um, Dark Souls 2 exists.

But it was only recently released. 

Xenoblade (Wii) and Ni No Kuni (PS3).

There are quite a few runner ups like Skyrim, Dragon Age Origins and Fallout 3. I love Dark Souls, but it is more of an action-adventure them an RPG...

Demon Souls

For me it's probably between Dark Souls, Witcher 2, Dragon Age Origins, and Mass Effect. It's tough to say which one I think is best though because I liked them all for very different reasons.

Dark Souls had the most amazing atmosphere, and I was just completely immersed in it. That, and I just loved the brutal simplicity of it all. It was a pure gamers game that just said hey, here's this amazing world full huge fantastical monsters for you to test yourself against. Go. Awesome.

Witcher 2 I loved above all for it's maturity. These days everybody is always quick to label their games as mature, but this game truly deserved that title. Everybody is quick to point out it's full nudity, but this game was really mature from top to bottom, especially with it's complex political plot motivations and intrigue. The game play was great, the graphics were spectacular, and it gave you some great influence on the story, but above all it just feels good to play a game where you really get the sense it was made for adults rather than kids who want to be adults.

Dragon Age Origins had a really awesome tactical element to combat that you rarely see in games anymore. Playing on higher difficulties really required you to micromanage every little moment on the battlefield as well as making sure you have the right party with a well complimenting set of skills for the various encounters. If you're a fan RPGs and strategy games like I am, that's a very welcome approach to gameplay. On top of that it had a great cast of characters, fantastic customization, and tons of replay value.

Mass Effect....what can I say? I love SciFi. I love space operas. I love RPGs. I love grand, epic stories. Mass Effect is the best combination of these to come along in a very long time (and unfortunately slipped from it's RPG roots in latter entries, but oh well). Amazing characters, impactful choices, and an awesome, fleshed out, believable universe. What's not to love?

Honestly couldn't tell you what the best one was. We had some great ones this gen

Breaking it down by platform is also a great idea.

PS3: Valkyria Chronicles -> FF13/Demon's Souls
360: Lost Odyssey -> Tales of Vesperia
PSP: Crisis Core -> Jeanne d'arc/Valkyria Chronicles 2/Tales of Eternia
DS: Final Fantasy IV -> Super Robot Taisen OG: Endless Frontier
Wii: Muramasa -> The Last Story

of the games in the poll, ive only played skyrim, mass effect 2 and valkyria chronicles.
Mass effect 2 had best story, but valkyria chronicles had better gameplay.
only note worthy thing about skyrim I thought was the audio, both in terms of voice acting and music.