Great timing, I am considering this very same topic myself. I've been avoiding a tablet until I actually need one, and I'm going to Europe for 3 weeks and don't want to take my laptop. I want a 7" so that I can throw it in my purse and use it for the walking maps. Apple is not an option for me because I just don't have that kind of money to spend.
Costco is going to have the Samsung Tab 2 tablets, both sizes, on sale on Black Friday at 9 am. I think the 7 will be about $150.
The Samsung has an SD card slot, but I've read that the Nexus 7 will accept a USB drive with the proper cord and a particular app. I don't care about the rear camera, I would never really use it since I have a great camera and a pretty decent camera on my Nokia in a pinch.
So I don't know what to do, but I have until Thursday night to figure it out.
Pros should stop wasting money on coaches and doctors and just read the experts on this forum.