unfortunately this happened to me.
i finished texting a friend and pressed the lock button.
I then immediately tried to unlock it and it never turned on again.
Battery pulls are not working for me.
This just happened on friday afternoon.
Now verizon is sending me a replacement which i wont see til tuesday
so im stuck without a phone. oh well. kinda miss the convenience of having a phone with me at all times.
a lil break wont hurt tho 
just a lil upset that this happened to me
Had the same problem with my four day old Droid this morning. Just would not power up and nothing happened when I plugged the charger into the Droid. White light would not come on.
Removed and replaced the battery and fixed the problem.
Hope it does not continue to happen . . . !! 
Ralph