I believe strongly in 2-hour services (for the main weekly service)... I feel the only exceptions should be if someone is receiving a breakthrough or tarrying, and even in those cases, I think benediction should be given and those who want to stay to continue worshipping, should be invited to do so, with everyone else given the blessing to leave.
The longest service I can remember in my adulthood (other than shut-ins, which are usually 7-8 hours), was 6.5 hours long. The service began at 6:00p on a Sunday night and it was over at about 12:30. The speaker spoke prophetically to LITERALLY every single member of our church (except me), and a few guests as well. She really took her time with each person, and spoke in great detail, and with great specificity. It was a blessing to everyone, but I won't pretend I wasn't really antsy and clock-focused. We could've been out by 11 or 11:30 if she didn't take so long with the offering. That was especially uncool.
As a kid, we had marathon services quite often. Sunday School at 9:00a. Assembly at 10:30a. Morning Worship at 11:00a. Usually got out around 3:30-4:00ish. Went to fellowship hall for dinner (unless someone was being baptized or tarrying or something, in which case we stayed put until directed to move). Then, after dinner, prayer started (usually around 5), service started at 6 or 7, and we were finished around midnight... and yes, we got up for school every Monday morning, and did family devotion every Monday night (our only night "off" from church).