I started Buzzgrinder.com back in 2001, but failed to snag @buzzgrinder a few years later, and now someone was sitting on it.
Since I owned the trademark to my blog (you did get your band / brand / company / blog name trademarked, right?), I was able to file a claim with Twitter. The Twitter Trademark Policy page is pretty straightforward, so it was easy to get my claim started.
After I submitted the proper trademark info and swapped a few emails with Twitter, I now have control of @buzzgrinder on Twitter. The whole process took a few days, and was quite painless.