Unfortunately, no for lists and boards (for the moment). Card delete has been added since launch. Trello blog gives the answer as follows:
Can I delete a board/list/card and make it go away forever?
Trello doesn't have board or list delete. Archive and close have a
similar effect. Card delete has been added since launch.
To delete a card, first archive it, then click delete from the sidebar
back of the card OR click 'view archive' from the board sidebar, find
the card, and delete it.
I've also found this bug annoying and contacted them.
I did the same thing, because I didn't notice the Google option at first. When I logged in with Google later, it showed me the same information as with my original account.
Just to make sure, I logged out, then logged in with my original account (Gmail address and Trello password), and it showed me the same information. Apparently if you use the same e-mail address, it automatically associates the two.
Best Answer
Go to https://trello.com/your/account and click Delete Your Account at the bottom of the page.