if Amazon has delivery on the release date, I will definitely go with that. Otherwise, I will suck it up and pay the sales tax and get it from Apple.
They delivered my 3GS on release day, so I trust them to do the same here. It must have been a big release too cause the UPS man said "enjoy your iPhone" even though the box was not labelled. Probably delivered the same package many times before that day. 😀
But yeah, if Amazon can do it on the delivery day it becomes a no brainer. For me, on the $499 model I plan to get, that's $50 in tax. I could add $20 and get a magic mouse too!