Here are the keyboard shortcuts ("hotkeys") for windows and Mac OS:

Windows:
cut = ctrl + X or shift + inset
copy = ctrl + C or ctrl + insert
paste = ctrl + V or shift + del

Mac OS X*: (and probably for older Mac Classic OSes, too)
cut = command + X
copy = command + C
paste = command + V

When I say "cut = ctrl + X", I mean in order to cut selected text, press the X key after you press down on the Control key first.

*I'm assuming that this is how Mac OS does it, but haven't tried it myself yet.

I'd also like to see undo (ctrl + z) and redo (ctrl + y, or ctrl + shift + z) functions, which shouldn't be too hard to implement (Swing comes with UndoManager and other classes for this). In other applications, I prefer to use a context menu for cut/copy/paste etc. functions. I know that some people prefer using an Edit menu from the menu bar instead. So there are at least three different methods to do the same set of operations. I say Chaqu'un à son gout, to each his own, whatever that floats your boat, whatever that tickles your pickle, ...

By the way, this thread at Open Discussions has a similar topic.

Update: Seems like drag & drop of text between LimeWire and MS Word works too (at least on Windows 2000).