I think you may want to test out your potential ideas. For example, if you are going with a .net version of your name, what is the .com version? Does that site clearly represent something else? Is it a competitor? Is it an offensive site?

If the site is for something completely unrelated but legitimate it may be easy to use the .net name as people you know may easily notice they should have typed .net. If it's offensive or a compeitior that may not be something you want to inadvertently point your clients to.

I bank at Citizen's Bank - but I did not know there are different Citizen's Banks. If I go to citizensbank .com it is not the same as my bank... but it's still a bank. You can imagine how frustrated I was that my user name did not work! It wasn't until I googled it that I realized there were two different banks and the one I wanted was citizensbanknc .com. Who would have guessed the NC? (For Northern California)

I almost gave up doing business with them out of frustration! But... I did automatically try the .net before googling.

Hope that helps a bit. I would go with .net over .biz (as for the tech thing, that was what it was intended for... but not how it's been used.)