Yeah the past half hour or so I've been all over the place reading conspiracy theories as well as the Bioware forums. Still don't know what to believe. I agree that there was no real payoff with all the decisions that have been made. "Oh hey, my buddies crashed on a planet and they're all ok!" I was expecting a lot more closure than that.
Though from what I've read, Shepard and everything else that happened with the Crucidble in that last 20 minutes of the game, was simply, a dream. Shepard dies when Harbinger beams him straight to the dome, which makes sense because I thought I had

ed up at that point (even though I was zig-zagging so I wouldn't get lasered :lol
The Synergy and Control Endings are what the Reapers want you to choose, which is why the Destroy ending seems so downplayed and wrong when the boy is explaining it.
Also note that the Destroy ending is the only ending Shepard wakes up, meaning he has broken free from his indoctrination. Some theories also suggest the crash where Joker and your friends come out of the ship is also a vision of Shep's damaged brain, right before he dies.
The theories are all along those lines. Saren and his plunge into insanity in Mass Effect 1 is also brought up and how it may explain the odd behavior (dreams) that Shep has in ME 3.
Who knows, but I think I'll spend all my time figuring out which theory makes the most sense, rather than settling for what everyone thinks really happened.