The search of Twitter handles becomes almost as crazy as the search for domains. Twitter names you would think are available to get are taken as frequently as domains you would think are free to register.
I am not talking about top keywords or geo names. There are so many people that sign up for Twitter even if they don't use it. So over the last year I have now had 3 potential sales on five letter .coms not go through. Two of the prospects assumed I had the Twitter handle and the last one just put in the email, "We are only interested in *****.com if you have the corresponding Twitter account."
All three Twitter accounts were active, and the deals just were not completed. Its funny sometimes I see short Twitter handles where the .com is available. So if you can get the Twitter handle for your top short .com domains it makes sense to get them. You never know if it prevents a possible sale. Again its not a must but might be good to have.