I have gone to Target the past two years...last year for one of the TV's, so got in line 5-6 hours early. At our store, they let 30 in at a time--and then every 30 seconds let 30 more in. We got everything we wanted, but we were in the 2nd group of 30. There were at least 500 people behind us. By the time we checked out, they had us wrap like a zig zag snake all the way to the back of the store. Probably waited close to an hour to check out.
I have also been to
Walmart and it is mass hysteria. Target does an amazing job. They come out several times with hot chocolate/energy bars--also warning people that if there is running or cutting, you will be sent out of the store. And they follow through with that threat. A crazy amount of people think they will be able to wait in their cars in line all night and then rush the store. People in the front of the line (me

) get very defensive about this...and the police are there to make a barricade so those people can't rush the line at the last minute.
I usually go just for the fun and the rush--I'm competitive by nature so just love it. But this year, there is nothing I "need" (like I needed the tv and PlayStation 3 DH talked me into last year

), so will be staying home and spending the night with my kiddos at their great-grandparents house--a tradition that I did for 20 years as a kid.
If you are just going for pj's and stuff, there was a year that we went back to Target later in the evening that still had all that stuff. Is there are Target near you that people don't frequent as often as others? If so, that would be that Target I would go to. If you go, have fun! I know I will be itching to be there.
ETA: I actually think lines will be worse this year because people don't have to actually spend the night outside like previous years. Only us die hards (crazy people) will spend the night outside. Normal people shop at 9pm all the time.