Disk Order, coded by some genius people at LikeMac (http://www.likemac.ru/english) is the best file manager so far for OS X.
People like me, coming from the Windows world, are accustomed to using Total Commander (former Windows Commander) coded by another genius Christian Ghisler. This is basically a file manager with two panes but you get to do anything with it, it can even replace your daily Windows shell.
Well, switching to OS X Leopard was painless except getting used to OS X Finder which is in my humble opinion a bit crappy :) I needed my Total Commander back, no luck, no plans to port it to OS X for the time being.
Disk Order (version 2.5.1 as of this writing) gets the job done pretty well, it can work with identical shortcuts with Total Commander. Go get the demo and see for yourself.