Calling All Photographers

It's finally time for me to invest in a new camera. I have a really nice point-and-shoot digital camera that has been loyal since high school...but with a summer full of real photography opportunities, I need to invest in camera that will see capture images outside of my daily life. So, I turn to all you bloggers out there who have amazing photos and skills. I'm looking for a camera that will take crisp and clear photos, a good zoom, and fast shutter time. However with most of my savings being set aside for my actual adventures abroad, I'm trying to keep my budget around $600. I am also looking at refurbished cameras.

So far I have narrowed it down to these two choices.
Nikon D5000 vs. Canon XSi

But I also know experience is much more reliable than website content and recommendations. Please let me know which to choose, what camera you have, which camera/lens you would recommend, etc! I can't wait to share with the photography that comes out of this new accessory :)
Thank you!