I enjoy waiting in line for releases. I did it for the 3G at a local AT&T store and it was not a mess like some of the large Apple store was.
I waited for midnight release Warcraft expansions in a mall. Now that was interesting. I don't play anymore (new baby kicked that habit) however it was interesting waiting in line for something you have been looking forward to getting.
The main reason I will wait in line again, it because I do not like to order online for new products. I always have that feeling like I am the guy who's order will get pushed back 3-4 weeks due to stock issues. I like to walk into a store and walk out with what I buy.
If I was eligible to upgrade, I would probably pre-order the new iPhone via Apple's web-site. But since I am unable to upgrade until August, I will be waiting it out. I will be looking forward to installing OS 4.0 on my 3GS though.
I'm on the fence about waiting. I would love to but i don't want it to turn into pure kaos. And i need to figure out exactly when to sale my 3Gs and align it so i won't be without a phone.
But alas i will have my iPad with me to keep me entertained if there is a line