UPDATE: While I haven't picked up any deionized water, I did try using a blank SD card. It did eventually get past the boot screen and I did briefly see the live tile home screen but it powered down after a while and then stuck on the boot screen again. (thx oldturkey & shortyshort)
Today, with the original SD card in, I plugged it into the computer where I synced with Zune and it started backing up pictures and videos. Sweet! So now it turns on. The physical buttons all work, including the camera, but not so with the touch screen.
Is there any way to revive the touch screen?