I've been asked recently about how to say numbers over one thousand: which is more usual, one thousand five hundred or fifteen hundred? Is there a difference between American and British English? And what's the limit for using hundreds, if any? 99 hundred? I don't think I have ever heard it.
It'd be interesting to know what this decade is called? The Noughties, the Zeros or something else? I'm also wondering if it's wrong to say twenty oh eight instead of two thousand and eight.
What you say will often depend on when you use it. There is no absolute rule, and basically you use what you are comfortable with.
This decade is still finding its way. I have begun to hear Twenty Oh Eight for 2008 as well as Two Thousand and Eight. It will probably settle into the Twenty Hundreds, just as the 1900s settled into the Nineteen Hundreds.