Linux is not Knoppix and the two should not be confused.

More importantly, I think Windows bashing and name calling (including common terms like WinBlows) do far more to hurt Linux and all it's distributions than it does to help. It's one thing to present Linux in a positive, even helpful light. It's quite another to bash windows and even insult windows users in an attempt to promote Linux. Overly negative anti-windows promotion is wasted on those who already know the merits of Linux, and only alienates windows users who don't know much about Linux.

I doubt that making a t-shirt is the best use of time to promote Linux, but if you have some t-shirt transfers that you are obsessed about using, I would suggest positive things like "Linux Expert" "Knoppix User" or even "Ask me for a fee Knoppix Linux CD". If you must bash something, then attack Bill Gates personally with something like "Damn You Bill Gates", as he is always pretty much fair game. But don't do things to alienate the windows users and make them dislike Linux.