I made a guest account, standard rights, thinking it would not effect any other accounts on my RMBP. Was I wrong. My computer has been renamed it seems, my backup shows the name of the user from whom I tried to use migration assitant on's time machine backup.

deleted all my printers and used the ones installed on the backup and time machine just wont backup now at all.

How do i change my backup name, now it Says "John Smiths MacBook Pro" Rather then my name as it was before? Even on the network, my computer is listed as "John Smiths MacBook Pro". Very frustrating.

I think this is what is causing the backup issue as its no longer the same name before. This is in mountain lion, latest updates.

You should be able to change your computers name in System Preferences >> Sharing at the top of the window.

I just went through a similar problem with my son in law who was using migration assistant to move data from a Windows computer to a new iMac running Mountain Lion.
I've had problems with migration assistant myself in the past, only because the results were not what I expected.
My son in law's situation was the same, the migration appeared to go well, but where are all my files?
I think Apple needs to do a better job of explaining what exactly is going to happen, (in regards to users, usernames, accounts, etc.)
The benefits of migration assistant are a great bonus, but mean nothing if they cause a novice-newbie to panic and do a total reinstall.

I've had problems with migration assistant in the past,
It screws up your keychain too, Especially if you change providers after you use migration assistant,
It takes forever to delete the old provider from your keychain.

I've had problems with migration assistant myself in the past, only because the results were not what I expected.
My son in law's situation was the same, the migration appeared to go well, but where are all my files?

If you've set up a user account, Migration Assistant does NOT merge user accounts - this is why you should migrate when the unit boots up the very first time. Once the migration completes, the files and data moved are in the user account moved - not the user account you're currently logged into. If you already put a pile of data in the new account you set up, it's all the more reason to merge data from a different computer on first boot.

If you've set up a user account, Migration Assistant does NOT merge user accounts - this is why you should migrate when the unit boots up the very first time. Once the migration completes, the files and data moved are in the user account moved - not the user account you're currently logged into. If you already put a pile of data in the new account you set up, it's all the more reason to merge data from a different computer on first boot.

Yes, a mistake I wont make again. I am installing mountain lion in parallels now, and will migrate from there, which will keep it completely separate from the rest of my system.

My only problem now is the last backup done on the time machine was incomplete, guess he shut down before it was finished. How do I go about selecting a different date in the time machine backup to use with migration assistant? Or should I just delete the "latest" folder and backup?

I would have installed from the time machine, but it does not give me options of not installing music, videos, applications, etc.