Porcupine Tree are such an amazing band. One of my favourites, for sure and I agree Wilson is a damn musical genius.
I'm surprised many are NOT mentioning Deadwing...why not? I just bought the 5.1 DTS version of deadwing for like $40 CAN and must say it was worth every dollar. Hearing this in 5.1 digital surround through my six kick-ass speakers brought a new appreciation for the album. Wilson did a phenomenal job mixing it - some of the vocals are ONLY noticeable from behind, it's just so damn impressive.
But yeah, some of my fave songs from the band are Shesmovedon, Trains, Prodigal, Arriving Somewhere, Start of Something Beautiful, Even Less, Mellotron Scratch, The Sound of Muzak, Piano Lessons and Heart Attack in a Lay By.