iMac and external Hard Drives.

Hello there.
5 more weeks till I get my new iMac.
I have one question about where to put all the different files.

1) Where should I put all of my streaming samples? I have Vapor, Kontakt, EWSO Gold, Battery, plus all the Apple Loops. Internal or External Drive?

2) Where should I put the files that are created when I record audio? External or Internal drive?

My iTunes music and Photos will go on a hard drive connected to my Air Port Extreme, so my huge music and photo collection won't be be a factor in taking up space on my internal iMac drive.

Thanks for all the help!