you want sum essential chords?? forget about chord books, all this jibber jabber. and learn a major barre chord, and a minor barre chorde, by leanring those TWO easy and i mean easy chord shapes, you instanty no a little over 20 chords, all you do is slide the chorde up and down the fret board and youre changing the chord nice and easy, all chords are essential but star with major minor, then go to 7ths then 9ths and wierd chords you cant pronounce the name of, it all takes time but just get to no the sounds of then and jam baby.
here is the major shape then minor shape


F major f minor
--1-- --1--
--1-- --1--
--2-- --1--
--3-- --3--
--3-- --3--
--1-- --1--
*notice they almost the same just one notes differnet also note the diffenct in sounds, major is all happy, minor sad. now just slide up half step, you got f# maj/mi another half step g maj/mi, so on and so forth

C Major c minor
--3-- --3--
--5-- --4--
--5-- --5--
--5-- --5--
--3-- --3--
* same rules go for those 2, the look differnt and so isnt the tone, so isn t just a little difernt sound that you can expeirament with and get differnets whatvers acroos ya no? try em out thier fun

Thats pretty much exactly what i did, and im happy.

Umm, I know a bunch o' chords, but just cuz I play jazz guitar and I play in a little band every once in a while and I have to know the chords....