What are some of the must have apps, add ons, etc... Anything special I need to know about this beauty? Treat the battery like an iPhone battery, right? Should I put some sort of skin on it?
Also have a look at the following links, as the information presented there might be helpful in your future endeavours into Mac OS X and could clear up initial confusion and may even prevent harm to your system or your files.
Mac OS X Basics
Switch 101 - guide with articles made by Apple on how to accustom yourself, after you switched to Mac OS X from Windows
Go to System Preferences > Sharing and enable File Sharing on the iMac and login to the iMac via the MBP with the name and password of the account you have on the iMac.
Go to System Preferences > Sharing and enable File Sharing on the iMac and login to the iMac via the MBP with the name and password of the account you have on the iMac.
I've found that Quicksilver has been really invaluable for my productivity! It has a little bit of a learning curve, but once you get it, you can save a lot of time and effort launching applications, opening docs and even controlling open apps.