A Mac owner (or technology geek) who is currently craving, or in possession of, the triad of Apple products, e.g., the Mac, iPad, and iPhone in order to impress friends or just have the newest and most hip trends to show off to everyone
Anne: "You're such a Macster..."
A mac, being a person that is good with women (macin on chicks), and a master is the best at something, we get Macster.
This word can also describe a guru of the Apple computers (for nerds)
nerd: "I need help loading Safari... where's the Macster when you need him!!!?"