I've had the same (same or some iteration close to it) for over 20 years, 25 maybe? I used to be Valhalla in the 90s but at some point it became impossible to keep it as the name was popular and used on multiple forums and sites.

Being a big Led Zep fan I had chosen it from Immigrant Song. So when it came time to change it I thought of their label Swan Song and just added my initials to it. I have a couple of other accounts for other purposes that are almost as old but not as meaningful as this one is to me.