Congratulations on your new MacBook. GGJstudios offered good advice and if you specify what you intend to do with your Mac, people can give specific recommendations. Also this topic tends to be asked a few times a week on MacRumors, so it is worth using the search facility to see some of the responses on the other threads.
Here are some of my favourite productivity Apps that I use on a regular basis, and should be useful to you.
1Password (Password, Form filling and Identity manager)
PDFPen (90% of the functionality of Adobe Acrobat at a fraction of the cost)
Alfred (App Launcher)
Dropbox (Cloud based document storage and sync App)
Textexpander (expands keyboard shortcuts into frequently-used text and pictures)
Skitch (Screen Capture and annotation)
Evernote (notes, sync files , save webpages, and share your ideas with friends and colleagues.)
DragonDrop (Utility to make moving files between folders much easier)
Moom (Tame those OS X Application windows)
Tweetbot (Twitter Client)
OmniFocus (Task Manager)