No biggie if your using IMAP if you delete it... you'd just have to reenter you info.... and your mail would still be on the server. I've never liked IMAP... I've always used POP (If your using POP and you delete the folder you would lose all your emails).
Well, I always like to set up the account from scratch again but FWIW, I'm pretty sure a file named com.apple.mail.plist holds these settings. A good way to test this would be to close Mail and drag this file out of the folder you find it in before reopening Mail. If I was near my Mac, I'd do it myself.