Hi Shante'
I'll see if I can give you a little insight on this. I'm sure other's with more social media skills will jump in and give you feedback as well.
MySpace - I don't use it, not much help there - sorry!
Twitter - I would say go with your first and last name, your business name is too long to use as your username. With that said if your first and last name is taken try a variation of your business name or your name. Just use good relative Keyphrases in your Bio so they can be found by search engines.
Facebook - I'm assuming you're going to set-up a FanPage so you will want to use your Business name. And, become a fan of yourself
LinkedIn - My account is in my Name. I've noticed when I do a search by company name, the results list is huge. Now if you type in the persons name search results are narrowed. Someone else might have more insight.
Hope this helps you some!