I was recently playing around with the design of my twitter page and got it to look like Garland, the default design for Drupal. A number of you have asked me about it, so I thought I'd publish the values I'm using. So, if you want your Twitter page to also look like Garland, you can input the following values into your Twitter design.
Of course, I'd recommend taking my website logo out of garlandtwitter.png, and putting your own image in there, but that's completely up to you.