I am a veteran of the lines and home delivery. I have bought every iPhone/Pad since the original. It all depends on what you are getting.
If CDMA, I wouldn't think the demand would be as great, but the supply will be far less as well. In other words, there may not be a long line, but you had better be one of the first.
GSM is a different animal. Depending on where you live, if you are not already in line, you might be too late. Seriously, you need to prepare to spend the better part of a day if you want one tomorrow. There is a reason the lines are longer at Apple stores; that's where the phones are. Waiting any place else is a craps shoot. Walmart might have 30 or so, if you're lucky, but Apple will have a thousand.
I was able to preorder this time. Honestly, though, waiting for the delivery truck is more stressful than standing in line. I keep the curtains open and wait by the door the whole time. Also, UPS delivers late in the day where I am. My doorbell does not always work, so I am always afraid of missing a delivery. I will be a basket case by the time it finally arrives.
Waiting in line can be fun as long as you prepare well. There is instant community among the line sitters. The atmosphere is quite festive. There are trade-offs either way. The worst decision you can make is to not take it seriously, get their to find that the line is around the block, wait for hours before you get in, only to discover they are out of the model you want.
If you can, go insanely early. See what the line is like. If it is fine, check back in a couple of hours. Measure the growing line against your pain point for waiting and the risk of not getting what you want. You will have only yourself to blame if you come away empty. There is HUGE demand for this phone. Don't believe the pundits.