Congrats on the purchase! I took the leap from point and shoots and camera phones to an interchangeable lens camera last year and I have been ridiculously happy since. Beware, just like aquariums, photography can be very addicting.
If you don't already have photo editing software that can handle .RAW files I highly recommend you invest in something. I use Adobe Lightroom. Apple Aperture is another popular program. Sometimes they have free trials to test them out. I didn't realize how much they can help recover highlights or shadows from difficult lighting situations.
Enjoy your new camera!