While you can copy (Command + C) and past (Command  + V) files in OS X, the cut (Command + X) function is not supported.  What you can do however is choose wether to Move, Copy, or Create an alias when dragging and dropping files.  

Command + Drag and Drop = Copy File
Option (alt) + Drag and Drop = Move File
Option + Command + Drag and Drop = Create Alias

As a side note, when working with files all on the same Volume/Partition Move is the default action, there is no need to hold the Command Key.  Alternately, when working with files across two different Volume/Partitions, Copy is the default option and there is no need to hold the option key.  You can always tell what is about to happen by taking a look at the curser before you drop.  A green Plus (+) icon indicates that the file will be copied, the absence of this icon indicates a move.

If the Cut and Copy functionality is absolutely crucial to your workflow, then I suggest checking out [OnMyCommand](http://free.abracode.com/cmworkshop/on_my_command.html).  It's a Unix and AppleScript Executor and if I recall, there are some user submitted scripts that will enable cut functionality for finder items.