What email address did you use to register? If it's an email address that was offered to you through a trusted internet service provider, ask them if it would be sufficient to provide contract details, maybe a copy of an identity card. There are still many ways to authenticate yourself.
I'd do both. Mining when you're not playing games or watching a movie and buying low and selling high. You won't get rich quick, that prerogative is only reserved for the extremely lucky. But you won't be left poor either if you're sensible. It's up to you!
My name is Daniel, I work as an IT-administrator and enjoy mining bitcoins, as well as the technical and economical discussions regarding our possible new currency. Oh and if you're interested, I am mining quite happily at 360 MHash/s