Re the Messiaen, Amen Soubasse! I'm working (carefully) on the Livre du Saint Sacrement right now; it's such an emotional experience. I have always thought of it as working with a different language myself. If you don't speak Italian, and are listening to an Italian person swearing in a gentle tone of voice, you might think "I don't understand this, but it is beautiful sounding." If you don't speak Czech, and are listening to a Czech person telling you how much they love and adore you, you might think "I don't understand this, but it sounds absolutely frightful." No offense towards the Czech language, of course, but it is very consonant-driven. Granted, some of Messiaen's earliest organ music is quite palatable, even when not in the mood to think.
I play the Widor toccata from time to time; it is a charming piece when not sped through like mad, but I prefer Widor's other pieces. Last Easter, I played the complete Symphonie Romane (first movement before the service, second during the offertory, third during the communion, fourth for the postlude); it is brilliant stuff, and much less extroverted than the toccata. The 8th is my favorite, though it will never be as likable as the 5th.
I do not, however, want to ever play Pachelbel's Canon again. Not in a wedding, not in my bedding, not in a house, not with a mouse (et cetera). I am absolutely sick of it. Also, I'm getting more and more tired of people who think they can "play" the Dupré op. 7 no. 1 trotting it out for postludes. Yuck. There are easier pieces out there.