Here's some non-intuitive things you might not have known about Skyrim Blocking:
* Bashing with weapons does much more damage than bashing with shields.
* Despite the in-game loading tips, Blocking with ANY weapon whatsoever is exactly the same -- a max 60% damage reduction at Blocking 100.
* The Shield Wall perk descriptions are wrong -- each level of Shield Wall actually raises your block by 10% each, so 2 ranks would be 20% (they add together)
* Block Runner and Quick Reflexes used together with a 2H weapon are incredibly useful and fun. You are basically a ninja at that point.

* There is a downside to blocking, unless you have turned off enemy kill animations with the console -- for the purposes of determining if an enemy does an instant kill on you, the fact that you're blocking at the time is ignored for the purposes of determining if you are at low enough health to die.
* The "Block Cap" is 85% damage reduction, which can be met with any weapon by having a 100 Block and 4 ranks in Shield Wall. You can lower the perk requirements by using a +Block Enchant. Don't ever get the fifth rank of Shield Wall if you plan on getting a 100 Block, because it's a waste... shields block a little better than weapons, and take even fewer perks to hit the cap.
-Loth
PS There's more... much more... in that thread that was linked above.
