OP:
Do you have any experience with any of the players in the SLR market? Have you shot with an (D) or SLR before?
As
jgrowl pointed out, your best option no matter what, is to head to your local photography store, and get a feel for each brand of cameras' in your own hands. Ergonomically speaking, I lean towards Canon & Nikon. Sony, Pentax, & Olympus are not comfy in my hands. However, by going to a store, you will be able to make that assessment yourself. Just keep in mind, usually when you start with a Body, you are buying into a System.
Is your budget of $400-$500, the most you are willing/ have available to spend? Besides buying a body, your going to need some sort of lens to start with, even if its just the kit lens, plus a Memory Card, probably a case, and if your knowledge needs a refresher, then a book on understanding photography/ composition.
Though the
TheReef pointed out In-Body Stabilization, don't let that be a selling point for you. There are Pro's & Con's to the IBS systems. But for now, you need to find a body that fits you, and works within your total budget. Once you have found a body, then you can start looking at features. One thing to keep in mind, is DO NOT, & I REPEAT, DO NOT, get caught up in the Megapixel Hype. Pixels are not everything.
Also besides buying New, you could also buy used from other Photographers', on sites like Fredmiranda.com, Photo On The Net, Nikonians, & a couple of others. I advocate buying used, because you have the power to stretch your $$$'s as far a possible, and still get very good condition gear for a great price. (All my shooting gear, has been bought used from other Shooters, either on FM or POTN

)