make sure whatever you use is for hardwood floors, if it contains any soap in it, it fucks up the polyurethane and leaves streaks. i have a cleaning lady, but what she uses is one of those mops where you attach rags and does a dry mop on the floors to pick everything up. then i have a hoover floormate to clean the floors... which you dont use every time... only when its actually dirty. it works like a shampoo machine where it puts clean water down and sucks the dirty water into a different container, it works awesome. heres a link for it:
http://www.amazon.com/Hoover-H3060-F.../dp/B0007MS5B2