A Thousand Suns, no question about it. As I was saying with Derek in the shoutbox last night, ATS is LP's Revolver, and LT is their Rubber Soul.
I like LT better, but without a doubt ATS has to be the most creative. They actually went out of their way to be creative, whereas MTM and LT were more of a comfort thing, to a certain degree.
I haven't heard LIVING THINGS yet, but I already know ATS takes the cake with creativity. Too many people like LT already.
A Thousand Suns. Hybrid Theory was them beginning their music. Meteora was them polishing their sound, but was pretty much the same thing. Minutes to Midnight had them experimenting different rock styles. ATS, however, was them experimenting on everything until they become obsessed with it - like a hallucination, which is why that gets my vote. Add all that = Living Things.
I voted for MTM. To me, it was the album that sounded the least like the traditional LP sound, and a lot of cool instruments and different vocal styles and stuff were used. The most being so was the entirety of HHH, the ebow effect on NMS, the SOTD intro, the cool synths, the tribal raw drums feel, the entirety of TLTGYA and a lot of the instrumentation of In Pieces.
Well, maybe MTM by a technicality: it was the first time they tried to do something other than nu-metal. ATS took it a step further, but hey, MTM could just as easily have been another Meteora if WB decided that was the way to go or if the guys decided they weren't ready to experiment yet.
MMM...COOKIES: Sweet Hamster Like Jewels from America! No doubt. Don't forget masterpieces like Bubbles and 26LITA.
LT has probably topped ATS as my favorite album but I have to go with ATS in terms of creativity. I don't think I've ever heard anything like Blackout and WTCM.
A Thousand Suns - No doubt about it. No other album measures up to that level of creativity. And I know a couple of people said, "Well, what about Hybrid Theory?" It was a creative record, but most people would say (myself included) that Linkin Park came late in the nu-metal game - they simply perfected the art of it.
I voted for Minutes To Midnight because well, each song is different - except for What I've Done - and not every song uses similar vocal layers which is pretty uncreative in my opinion. To me, A Thousand Suns was boring as fuck. Blackout and When They Come For Me was the only creative song on that album but Blackout was the only song that wouldn't bore me. Living Things, well, it's very typical Chester-pitch vocal with Fort Minor and Dead By Sunrise similarities which to me is not creative at all. This is purely my opinion.
I would normally say MtM on something like this, but I chose ATS because it was truly more creative while MtM was just a risky change for the band more so than the fans.