Where Did My ALT Key Go!!

I am currently loving working on a Mac, but the one nagging thing that I miss is the fact that I can’t hit the ALT key and have all of the menu accessors enabled so that I can traverse the menu by hitting ALT – Followed by series of keystrokes. I much prefer ALT based navigation to having to memorize different shortcuts CTRL + Key or now Command + Key.

Am I missing something or is there no equivalent in OSX?