This is my first time using the Nxt wallet. I first downloaded and installed it from
http://nxtra.org/nxt-wallet/ (Mac version). Upon first installing the wallet it selected a randomly generated 12-word passphrase for me and gave me an account ID. I closed the wallet and then reopened it. I entered a different passphrase than the one initially given to me to see if the wallet would still give me access. The wallet gave me access to the dashboard but I observed a different account ID than the one given to me when given the randomly generated 12-word passphrase. Is this normal? Why do I get access to the dashboard and see a different account ID when entering an incorrect passphrase? I guess this stresses the importance of never losing you passphrase; otherwise you have no way of accessing the assets tied to a particular account ID ... I think.

Yes, the passphrase defines the account (brain wallet). If you enter a different phrase, you open a different account.
So... never lose it!

mmmh, brain . . thats my the problem, right there, mine is small . . So, I use "Key-pass" 2.xx (generates loong, raandom, passwords), use with "Data backup" - plug in, and I have backups on USBs, etc. in different locations.
It was said several times before, but you can´t repeat that often enough (sticky? mods ! ) ! !
Oh, and switch it to "auto-type obfuscation", and "secure desktop" to enter your master-password !
At first, its a bit of work, to set up, but then it lets you finally sleep sound, and dream of your wealth . .

How do you set up "auto-type obfuscation" and "secure desktop"? I am using a Mac. Can you provide a link or is there a better way? I don't like the fact that I cannot change my passphrase. Need to make sure my computer is always free of viruses.