I am a recent convert too (< 1yr). If you are moving over from Ubuntu,the transition will be less traumatic. First thing to figure out is the "state" of dock ic

I am a recent convert too (< 1yr). If you are moving over from Ubuntu,the transition will be less traumatic. First thing to figure out is the "state" of dock icons. There is a little halo under the dock icons that tells you have an active window. Then figuring out the Apple+Key convention as opposed to Ctrl+Key convention. Also figure out the ease of installation and uninstalling apps, which blew my mind. As for the apps, get MacPorts and get meld for file compares. SmartGit client is great. TextWrangler is great too. Figuring out how to get all vim extensions. Actually figuring out the "package" architecture of an installed app is also important.