I think the Cost of Living ep by the Clash is one of the best ever. All 4 songs could have been singles. 1. I fought the law 2. Groovy times 3. Gates of the west 4. Capitol Radio Have a listen and can you beat this.
My "Best ep of all time" would be.. Senseless Things "Andii in a Karmann" It never got released due to record company bankruptcy, and some of the tracks got issued on singles, but it's six tracks and make up a perfect mini-set
I don't know about "the best" (or even that there is such a thing) but the one I listened to a couple of hours ago is a favorite (it's referred to as a "mini album" so maybe it doesn't count... I love it anyway): Rain Parade – Explosions In The Glass Palace Genre: Rock Style: Alternative Rock, Psychedelic Rock Year: 1984
Tool - Opiate 1. Sweat 2. Hush 3. Part of Me 4. Cold and Ugly 5. Jerk Off 6. Opiate Straight to the point and I still love it
Some people call 10" LPs, like this one by Urbie Green on Blue Note, EPs but I don't. Would love to have a copy of this all the same, whatever you want to call it.