Having lost about 10 Eyes of Ender in lava near a stronghold then soon after locating the portal which needed, you guessed it, 10 Eyes of Ender, I went back to grinding Endermen for more pearls at a sort of outpost/watchtower I made some time back on a plain. Formerly I would stand on top of my tower and when some Endermen showed up nearby I would look at one and hop down into a pool below, then attempt to slay them. Unfortunately I would still get a little sloppy sometimes and get slapped by various other mobs who would close in, or sometimes take on two or more Endermen and not keep an eye on my health, thus dying quite a few times.
Sooo I figured I would make some Iron Golems and see what happened, though assumed they were only really any use for protecting villagers and were likely to wander off. Boy was I mistaken. As soon as I lured an Enderman near a golem it got absolutely battered, in part because it doesn't seem to teleport out of its reach at all. It soon became a very nifty way to build up pearls, with the added bonus of the golems attacking Skeletons and Zombies too (though seldom Creepers sadly). They are prone to wander away or sometimes go into a sort of daydream, but you can tie them to a fence or just leash them and bring them back if they go too far. I eventually built a 2-block high wall around the area which kept them in.
Now back to the Nether for a bunch of Blaze rods...