My advice to those still looking is:
Folio/Case vs. Sleeve
Get the folio or 'case', preferably leather.
You will find that when you need to get to tablet quickly to work you don't want to unzip and deal with taking it out of something.
Just flop open the case and off you go.
This also keeps lazy people from hurting the tablet.
If the thing is always contained but accessible, it's more likely it will stay protected.
Case border
There are some cases that put material
on top of the frame of your tablet.
I do not find these that attractive.
The best ones are leather and have small C-shaped clips or hooks that grab the
edges of your tablet and hold it snug.
This allows the full glass surface of tablet to be exposed making finger gestures easier, as there is no edge to bump up against
Leather
You are gonna hold this thing a lot, possibly all day.
Leather just feels good to the touch and smells nice.
I'm ok with plastic on most stuff but for some reason really like the feel of this leather.
The one I got this one
Amazon.com: Acase(TM) Acer Iconia Tab A500 A501 High Quality Premium Slim Leather Case Folio with built-in Stand for Acer Iconia Tab A500 A501 10.1-Inch Android Tablet Wi-Fi / 3G 4G (Black): Electronics