Piano Lessons

First off, incredible song. Great lyrics, and an incredible atmosphere.

That being said, let's dive in

As was mentioned by others, the song seems to be about Steven Wilson's musical career up to this point, and his frustration with the music industry in general. He starts with his humble origins:

"I remember piano lessons The hours in freezing rooms Cruel ears and tiny hands Destroying timeless tunes"

Here he reflects on his beginnings as a musician, as a young boy with a terrible ear for music taking piano lessons, practicing for hours on end, destroying beautiful pieces of music with constant mistakes.

"She said there's too much out there Too much already said You'd better give up hoping You're better off in bed"

Here we have someone, "She" most likely being his piano teacher, or some other prominent female figure in his life (mother perhaps?) discouraging him from pursuing his musical studies any further, telling him he's wasting his time chasing a dream that's almost impossible (there's too much music out there already, everything's been done). As an adult, "she" understands the music industry, (if "She" is in fact his teacher, its a good chance she pursued similar dreams in her youth, and was probably crushed to find out that being a musician is nothing like she dreamt it would be) and is trying to steer him away, telling him:

"You don't need much to speak of No class, no wit, no soul Forget you own agenda Get ready to be sold"

Here she's explaining to him that if he wants to be a successful musician, he has to understand that there's more to the industry than just creating music, that to a producer, selling is more important than the actual creative process (you don't need much to speak of, no class, no wit, no soul, because these things don't necessarily sell albums), and that most of his ideas are going to be taken and turned into something different (something safe and marketable; radio-friendly)(I come in value packs of ten (in five varieties))

"I feel now like Christine Keeler Sleepwaking in the rain I didn't mean to lose direction I didn't want that kind of fame"

Now here I can't say anything for certain, because I honestly have no idea who Christine Keeler is (though if the other comments are correct, I see how it fits in), but this line seems to jump ahead from past to the present time, Wilson has reached the success he was told he would never reach, and now that he has it, he's saddened by how much he has strayed from his original dreams, nothing is how he expected it to be (just as his teacher told him all those years ago). He probably feels like he's been sleepwalking his way to fame, like he hasn't really earned his place, since many of his ideas have been changed from his original intentions.

"(Take your hands off my land)"

This seems to be his statement to his producer, telling him to keep his hands off his "land" (music), basically, "I'm the musician, I know what I'm doing, give me the freedom to do what I want".

"Credit me with some intelligence (if not just credit me) I come in value packs of ten (in five varieties)"

More of the same here, "Give my music a little bit of credit". The value pack line is a great metaphor for how his art is being commercialized.

*brucifers idea about it being about his fingers is another great interpretation, one that I hadn't thought of, but adds a whole new dimension to the metaphor.

"And even though I got it all now My only stupid dream I see you and me together And how it should have been"

Here he yearns for his dream, the way he wanted it as a child.

"I remember piano lessons Now everything seems clear You waiting under streetlights For dreams to disappear"

To me, this last line seems to be a final reference to his music teacher. Wilson thinks back to his youth again, and having seen the music industry for himself, he has a new perspective on what she told him, and understands why she said what she said. As a child, he probably thought she was just being cruel, perhaps out of jealousy, but now he sees that she was trying to warn him. He sees her, "waiting under the streetlight", waiting for Wilson's dream to wither and die, just as hers did.

Just my 2 cents.