My first 4 AG batches have been 7 - 8 hours but every one of those I added something new. The first batch was with a BK and a cooler using gravity. Second batch I added a MLT. Third, I added a pump, then I added a HERMS coil in the HLT. And just after this last brew I upgraded my 12' copper coil with a 25' stainless coil and bought a second pump. I hope to finally have my system they way I want and hope to eventually get brew day down to 6 hours or less. I'm probably going to start doing 10 gal batches too, just to end up with more beer for the time put in. Plus it sucks when you make a great beer and kick the keg in a month. I'd love to just plug in another keg and say, "I got more where that came from".
Short answer 7 hours.