Be aware that the general model of the clipboard in X is different - quite a bit more complex - than it is under Windows.
It takes some getting used to, but is pretty cool once you figure it all out.
Basically, there are 3 clipboards - called Primary, Secondary, and Clipboard. Which one gets pasted when you invoke a "paste" operation is somewhat fuzzy.
A useful thing to do is to install the package called "xsel", then you can do the following commands to see what is in each of the 3 clipboards:
$ xsel -s
$ xsel -b
Yes, it is confusing that one of the clipboards is called "clipboard".
And, yes, I know that technically these things are called "cut buffers" or something like that, but I just call them clipboards.
Finally, each of the above commands can be given the "-i" option to put text onto the clipboard. For example:
$ ls | xsel -ib
will put the output of the ls command into the clipboard clipboard.
And so it goes from there...
GitD's list of things that are not ready for prime time:
2) 64 bit OSes
3) USB 3