Not necessarily a regret, but I'll be buying a name change thanks to ANet taking 3 motherfucking months to do what they said they would do in 24 hours. Yes, indeed I am bitching about how long it took them to release GW1 names that were reserved and then unused in GW2. And now I've spent another 4 months wasting a character slot to hold the name. Now, I wouldn't be this bitter if it wasn't for the fact that I went to customer support - not once, but twice - and posted on the official forums, only to get the answer "we won't be releasing them at all" and no response, respectively.
Ah well, at least I can finally change it. I love the number of people that got a sex change for their character and still have a name that is clearly for the opposite gender.
Edit: Whatever happened to Drakewurrm, he would commiserate with me on this one.