Hand sanding or power..hmmm..depends on how enthusiastic you are..just kidding...on a more serious note,yeah I would recommend a drum sander and if you want to save more time also rent an edging machine(just like it sounds,works along baseboards and other hard to sand areas).As far as technique,for t&g flooring sand along the grain back and forth, for parquet sand in opposing diagonals.As far as problems..man get yourself a good respirator,IT GETS DUSTY,and just a suggestion,if you have a window fan,use it w/a air conditioner filter on inside,traps alot of the dust so your fan doesn't get mega cruddy.Also match the grit of the drums and disks to your type of flooring,I'd need more info as to what you have exactly before I could recommend them.Oh and another thing,if you don't want the wife whacking you over the head w/a rolling pin,seal all doorways w/plastic.