For me, it's clearly the two Souls games. It's also the only series I am eagerly hoping/expecting for another and another and another iteration of it to come to whatever platform. The more powerful, the better.
I very much liked Bioshock, but the second one already felt like a rather dull reboot of sorts, with a bit of gender equality thrown into the mix. And since the third one went into an annoying bout of pre-release spoiling, which, combined with an autoplay feature some websites consider to be good fun, it just already pretty much took out all the steam and dreams and hope I had going for it. So, no, there's no 'series' for me to like there. IP laws be darned, the soundtrack discs/goodies were some of the most underwhelming things in the last decade. Get those darn IP laws fixed, they're just no fun no more.
I really want to like The Witcher, as I think it's mostly brilliant, but the battle and mere moving around feels like sore ass to me. Can't stand Ass Creed, can't stand Mass Effect, detest Dragon Age 2.
What else?
I really like the Portal games, so I think that's another 'series' of sorts, even though the tiny, simple, pretty ugly first one has more replayability than the all-made-up second coming... and the coop/multiplayer bit got boring really, really fast.
Even though they all were pretty much broken or at least easily breakable, I loved the S.T.A.L.K.E.R. games. Great atmosphere that was really multiplied with the Russian voice-acting. The feeling of dread, of being lost & alone in a well messed up world was insanely more prominent in the first S.T.A.L.K.E.R. than in, say, Fallout 3.
Ah, yes. Fallout 3 - I love and respect the first two games from a thousand years ago. I kinda like Fallout 3. I don't like the Bethesda looks of, say, 99.9% of all the characters, and I really have severe issues with the Bethesda inventory system. But still - Fallout 3 was one of the first 'modern' games - with an aging and ailing bouquet of engines - that saw me clock in well beyond 100 hours, and enjoying myself most of the time. Fallout NV - pretty strong MEH from me there, so... we'll see. If another one comes out that doesn't involve too many Mad Max fake Romans and it isn't located in Las Vegas, we might find some love again. Yes, I know Fallout is not a new IP per se, but 3D Fallout that isn't complete random bollocks is kinda new.
I very much enjoyed Heavy Rain, but it's a tough one to follow up. I just don't see myself playing a dozen of these 'interactive experiences' and some glitchy bits turned the unfolding drama into an insane LOL-fest - laughing so hard we almost broke our backs, died of lack of oxygen and fell off chairs and sofas when we least expected it. It's been a while, so I'd definitely give any new IP in the same vein a spin, though.
Special mention needs to go out to Brütal Legend and Psychonauts. There's a guy that moves in mysterious and pretty random ways, but I really enjoyed these two games. The silly item-seeking knight abomination, though, saw me bored and losing hope in just one sitting. That was pretty crap.
