As many have said, it depends on the trip.

I just got back from Hawaii, and was packed to the gills. I knew it was going to be raining (it's Hawaii afterall) so I had to bring more clothes than I would normally. Plus, it's Hawaii, so I had to bring my camera gear, which requires multiple lenses (I only brought 4 of my 6) plus a tripod, flash, charger, lense cleaner, external batteries etc. Add on to that laptop and ipad, charger for those, and phone chargers, etc, you get two very packed bags. If I'm just going to NorCal or something I could do it in one bag. If I'm going to Vegas (I do quite a bit for a night or two) then I need to take more clothes to avoid smelling like an ash tray, but can take smaller bags since I don't have camera gear.