dmbaer
bitflipper
I almost always play with eyes closed
You told us once about a gig you had where the audience was a swingers club. Keep your eyes closed for that one? 
I did rehearsals blind folded for the actors, and the result was ... that your ears perk up a bit more and you can (eventually) find the location of the voice (tested it several times) and you know how to move. It's actually a very handy tool to learn to use, as it has the upside of teaching you how to work with the set pieces a lot more, than you might otherwise, when you kind of ignore the table and the chair next to you.
For music, I can't really say, but I would imagine that it enhances the listening ... and you can always look at any blind music player and they are always very sharp on the listening side of things, specially in music. Rachel Flowers comes to mind ... and seeing her play with an orchestra, do a piano solo, or with ZpZ, kinda changes this game some ... and even she does not explain it well at all, in her interviews ... I think people are intimidated into asking her about the "blindness" and how she sees music. I would think it is too facile and weird to just think of it as a sort of mathematics, but something else is in there when she does as much as she does ... at least you knew that Ray Charles, Stevie Wonder and others, kinda did the same thing nicely, but Rachel has taken that to a different stage altogether.
Just go listen to her complete piano version of TARKUS ... it becomes one of the great compositions for piano, and even makes folks like Keith Jarrett look a bit repetitive, and mechanical.