Is a leveled wood frame for a basement floor a good idea?
I have a basement floor that is concrete. 

When we finished it off, we used a product called DriCore as the sub floor.  



This is a plywood with a plastic bottom.  It's specifically designed for basements, and it raises the floor a little bit.  The disadvantage is that you essentially do the floor twice. :)  Also the cost is higher.

With that said I have had this set up in place for about 4 years now and it works well and looks great!