@maxdancona,
I agree - the US by its basic principle is freedom. So you have the freedom not to stand or to stand. I personally think it is respectful to stand, however, given everyone is free and others have different viewpoints so be it if you decide to sit - as long as you are not impeding on my rights.
As far as an alternative - if it makes you feel better sure recite what you want or nothing at all.
I think people make more of things than is even necessary....When I was in high school there was a lot being brought up about religious rights and so forth. The pledge wasn't an issue - but the moment of silence was. Although I did not know one student who has an issue with the moment of silence - and honestly I didn't know what that moment meant in religious sense as it was a moment of silence not a moment of prayer.
In any case, the school decided to open it up so as to offend anyone. They decided that during that moment - a student could say they wanted to pray, sing whatever the heck they wanted and if others did not want to participate they could be silent or walk out into the hallway.
Well with a bunch of teens just imagine what happened - that 60 seconds ended up with most of the teens in the hallway screwing around. My earthy crunchy sweet heart of a homeroom teacher gave some suggestions of the use of the time - we did this thing where we all joined hands bent forward and as we went back up just went "Ahhhhh" - she even had us singing Kum ba yah - to this day I don't know how she got us all participating but we did.
Long story short after about a month --- the school decided to go back to the moment of silence-where you just sat there quiet for a minute.
In other words - the moment of silence isn't about prayer (it can be to you personally) but can be just a moment to reflect, daydream or even sleep.