It's anybodies guess how long it will take there, it all depends on how many planes come in when yours does and how many lanes are open. My last time through (December) we were the only plane, and getting to immigration there was nobody in front of us. We were the second in line at the booth for immigration.

Pick up your bags, and zip right out of the customs line, that is usually not a delay at all.

You didn't say if you were a US Citizen or not, so if you are not all of this probably wouldn't be valid, that line was a bit longer.

I have also been in line for about an hour to get through immigration, it all depends on the number of flights.