I dual boot with Ubuntu on my Macbook. For anyone thinking about making the switch, it is really easy.

My primary tools for daily life:

-> Instant messenger.

-> Email client.

-> Web browser.

-> Text editor.

Both MacOS and Ubuntu Linux have excellent working options for each, so I don't miss MacOS when I'm in Linux. Infact, sometimes I miss Linux when I'm in MacOS.

Oh.. and if you're dual-booting, Ubuntu mounts the MacOS partition as read-only, which is great for being able to access stuff in my mac partition.