I think his best is "Don't Shoot Me I'm Only the Piano Player." I love all the songs on it. That and it came out when I was in high school. "Crocodile Rock" was popular and my girlfriend's name was Susan. ;)
That album is pretty awesome. It's so mysteriously missing from everyone's collection who claims to be familiar with Elton's classic years. Then again, so is "Tumbleweed Connection" which i think fairly ties "Honky Chateau" as my top pick for EJ album(s). I'm still waiting to run into a "Honky Chateau" Tour live bootleg. I found "Tumbleweed Collection" way before the deluxe edition just recently released all the demos/live versions worth listening to. Or for the Honky Chateau Deluxe Edition, if it is ever gonna come out.
I think most often I read that Goodbye Yellowbrick Road is Elton's best but my personal favorite is Captain Fantastic and the Brown Dirt Cowboy ! Second to that is the Fox.
I just listened to this album again and High Flying Bird has to be one of Elton's most incredible melodies ever written ! Check it out and listen with ear buds, preferably the remastered version ! Great stuff.
"Captain Fantastic and the Brown Dirt Cowboy" is my favorite, but his catalog is so extensive it's hard to pin down 'best' albums. Even picking a top ten is difficult for me!