That's hard to say. I was so excited about the Pre last year that I couldn't sleep and ended up being the first person at the store at about 4AM. By the time the store opened there were 40+ people in line behind me, so I was glad that I waited restlessly outside the store as opposed to waiting restlessly at home.
BUT, I think the situation with the EVO is different. From what I have read and understand, there will be more inventory for the EVO than there was for the Pre. Palm was cash strapped and couldn't make boatloads of them for the first day, but HTC should be different. If it's anything like last year, when the time comes closer to the 4th you can guage what you should do by reading what everyone on here is planning on doing.
Also, it seems like a LOT of people on the forum have pre-ordered at Best Buy or Radio Shack, so if you are going to a Sprint Store, there shouldn't be as many people there. With the Pre, the BB's and RS's only got a few Pre's each, so most people just went to Sprint.
Hope this helps!