I'm sure some of you have spent much more time in embassies and seen more of them than I have, but I have had the opportunity to visit the US embassy in Beijing a couple of times last summer.
The first was for a presentation on what not to do in China and what they could do for us if we did screw up. It seemed like a fairly secure place, but I remember looking for the Marines and never finding them. We had to go through security, but it was only Chinese guards. There were only about 50 or so of us there that time.
The second time was a few weeks later for an Independence Day party. The place was packed with all sorts of international VIPs, and the party was awesome. The only security we went through that time was some Americans making sure our names were on the list and some Chinese security guards. We shut the party down, and one of the guys in our group walked out with a tall can of beer and a piece of melon in one hand and a tall can of beer and a piece of corn-on-the-cob in the other. He made it all the way to the subway station before finishing.
Both times, all electronics were held at the door until we exited.
The place seemed secure enough, but our embassy definitely looked less "fort like" than some of the others (Israel if I recall correctly) on embassy row.
Thankfully, I'm not in the position to make the the decision on the best way to respond to these embassy attacks. However, I feel something needs to be done in response. To me, attacking our embassy is essentially a declaration of war. Do we need to invade these countries? Not in my opinion. I feel we should pull out all people and funding and let them try to make it on their own. If they become hostile and harbor terrorists, bomb them back a couple of decades to the stone age.
What seems to be the greater crime here is the lack of ability to defend the embassy from attack. An attack on a US embassy may be "successful," but those that actually make it in should have to climb over the bodies of the first few waves of attackers to do so.