If you are serious about blogging be series about what you call your blog. In order for people to easily spread the word about your blog you need a easily rememberable domain name.
People often talk about blogs they like when they are speaking to friends in the real world (that’s the offline world, you remember that place right?). You need to make it easy for them to spread the word and pass on your URL.
Try and get a .com if you can and focus on small easy to remember domains rather than worry about having the correct keywords (of course if you can get great keywords and easy to remember then you’ve done a good job!).