Mike Portnoy has left Dream Theater.
Like most, I am a bit stunned... but quite honestly not surprised either. As Mike stated, after doing shows with Hail, Transatlantic and Avenged Sevenfold, he realized that he was having more fun with those things that he was with Dream Theater. And I have to second that. In recent years I have enjoyed his side-project stuff much more than the DT stuff. They kept it up for 25 years, so it's not like they didn't have the chance to explore the world both physically and musically. It'll be interesting to see what sound Dream Theater will have without Mike (as DT is still planning on recording a new album in Jan 2011).
One disappointment is that there will not likely be a completion of the DT-project Mike was working on which involved writing a song for each step of the AA 12-step program. All of the songs were created so that, someday, the whole 12 song suite would be able to be played seamlessly together. The last album had part 9 and 10 on it, I believe. So the upcoming album would have likely completed this suite.
However, another disappointment was avoided. I'm glad that I got to see Dream Theater live (at one of the best concerts I've been to, too). It could have ended like it did with the Grateful Dead where I had the chance to go to a concert and said 'I'll catch them the next time around' and then Jerry died. So, no regrets on my part for the past few DT concerts I've missed. I saw them once (with Fates Warning and Queensryche, no less) and it was awesome.