Haha, funny you should mention the essential plugins.
First off, Essentials
http://forums.bukkit.org/threads/gen-sec-econ-tp-admn-essentials-v2-3-a-collection-of-useful-commands-and-features-860.15312/ it's probably the most used plugin ever, VERY VERY Helpful, adds like 120 commands.[Also has your /back command and /who ]
Another cool, popular amongst the peasants plugin is ChopTree,
http://forums.bukkit.org/threads/fun-mech-choptree-1-23-chop-trees-by-removing-lowest-block-like-cacti-818.15566/page-10#post-392886 and it makes it so when you break the lowest part of a tree, all of the logs break, which is a little more realistic and VERY Helpful.
WorldEdit is rediculously helpful but rediculously hard to learn, but it allows you to.... oh just look up videos, its too awesome and complicated to put in words... Anyways, you should also look up videos of WorldGuard as well, as the two make a great pair. The links:
http://www.sk89q.com/projects/worldedit/ http://www.sk89q.com/projects/worldguard/
