Wallet.Dat

[The 4ner]

Is the wallet.dat file all I need to be able to have access to my BTC again?
I recently purchased a new iMac and have downloaded the latest version of Bitcoin-Qt.
I have the wallet.dat file stored on a USB. How do I access my old addresses? Please help.

I've been away from the BTC community for months. I've forgotten a lot of the basics. 

[jackjack]

Yes
And the passphrase if you have any

[shorena]

-snip-
I have the wallet.dat file stored on a USB. How do I access my old addresses? Please help.
-snip-

Shutdown bitcoin core. Copy your wallet.dat in the folder

Code:

~/Library/Application Support/Bitcoin/

[1]

your OS should ask if you want to overwrite the file that is allready there. If you did nothing but sync yet you can just overwrite it. If you have used one of the new addresses you might want to make a backup first.
Start bitcoin core again. It should detect a new wallet.dat automatically and rebuild a database. Depending on your machines speed this might take a few hours.

[1] https://en.bitcoin.it/wiki/Data_directory#Mac

[The 4ner]

Got it. Thanks for the help everyone!   

I haven't used any of the new addresses so overwriting the new wallet.dat file should be okay.

Here are my computer's specs: Processor  3.5 GHz Intel Core i7
                                                             Memory  32 GB 1600 MHz DDR3
                                                             Graphics  NVIDIA GeForce GTX 780M 4096 MB
                                                             Software  OS X 10.9.4

I'm sure it's powerful enough to rebuild the database in no time, or at least I hope. 

Thanks again guys! I'll leave some positive feed back to y'all as a thank you.