There are a couple keyboard cases coming in January if you don't want Dell's, which apparently will probably come in January as well. Otherwise, anything works fine. Bluetooth would be best so you won't have to use the USB port, unless you want to always use a powered USB hub, which I believe won't charge the tablet. There are a couple Logitech ones that I'm interested in, but they are pricey.
I highly recommend logitech K810 bluetooth keyboard. I use it with my Venue 11 and couldn't be happier. It's rechargeable battery lasts a long time AND it's backlit. emoticon.Cool.title