I have tried to come up with a top 10 albums list, because narrowing it down to just one is darn near impossible. Here are some of my tops though:
1. Moving Pictures by Rush. It is the perfect synthesis of Rush's progressive tendancies, focused into concise, dare I say radio friendly songs. It is a moving, anthemic, thoughtful and focused album. Brilliantly done.
2. Second Life Syndrome by Riverside. This is a relatively recent album, having only been released last year. However, that doesn't diminish just how amazing of an album it is. It is emotionally gripping, marvelously written, and one of the most cathartic musical experiences I have ever had.
3. Blackwater Park by Opeth. Some albums define genres (like Nevermind did - and still does - for grunge). Others defy them. Blackwater Park is one such example. Is it death metal? Is it progressive metal? Is it psychedelic? Is if acoustic folk? Yes, yes, yes, yes and then some. That and the fact that the title track, "Blackwater Park" is my absolute favorite song ever, I can't pass up mentioning this disc.
4. The Human Equation by Ayreon. No one, and I mean no one, comes close to the rock opera prowess of Arjen Lucassen. No one. And The Human Equation is the perfect example of what a rock opera should be. A coherent story, powerfully told through quite possibly the most impressive cast of vocalists ever assembled for a rock album, with the stellar songwriting of Arjen, it just doesn't get any better.
5. Disconnected by Fates Warning. This one makes the "Favorite" list, though I wouldn't argue that it is Fates' best album. They have too many. Heck, Jim Matheos has written more obscenely good songs than any one person has a right to. And while I wouldn't try to assert that Disconnected is Fates' best, it is my favorite of theirs. It is the album that really introduced me to Fates Warning, and got me hooked. It is a moving listen, melancholic, outraged, and hopeful. I love it.
Put a gun to my head, I would probably go with Moving Pictures, only because I have been in love with Rush for most of my life. But any one of those albums deserves that top spot.