Vacuum or sweep?

Okay, so for you that have been to our house, you have seen how much hardwood flooring we have.  And for you that know me well, you know that I am a major clean freak!  I have tried everything to get it clean!  Mopping isn't so much the problem, its keeping it clean between moppings.  It takes me about a hour to sweep our floors, and even then they don't look great.  Does anyone know of a vacuum that is made for hardwood floors that won't scratch it?  I bought the Swiffer vacuum, which works okay and it is quick and light weight, but the battery died after a few months.  Sure, I can just buy another one and replace it every couple months, but if anyone knows of a vacuum or a shop vac that works better, please let me know.  

My back is killing me!  And it never fails, right after I clean the floor, Clayton decides he doesn't like what he is having for lunch, and the next thing I know, my floor is a mess again.  I need something I can pull out quick and use a few times a day.