They are, for the most part, all pretty amazing. My favorite is either early mothers or his fusion jazz/rock period.
When he played: 'The Royal Festival Hall' London in October 1968. I have the concert on 2 C.D.s: 'Ahead Of Our Time' & 'Weasel's Ripped My Flesh' . He played 'The Royal Albert Hall' in September 1967. I also have some segmental footage of the R-F-H concert on my 'Uncle Meat' Video-Tape. I could have seen Frank Zappa at the Hammersmith Odeon in the late 1980s but I thought I'll see him later; - then suddenly he was dead. My favourite Zappa period: 1967-1968.
I;m listening to his Uncle Meat album right now Zappa kicks every psychedelic band's ass. And he made his music so much more trippy than other bands who swallowed acid like breakfast cereal. ZAPPA DIDNT EVEN USE DRUGS!
Just Another Band from LA was always the one I seemed to like best. Apostrophe and Overnight Sensation a close second. Good sounds all the way thru. except for Ship Arriving Too Late... that one never did it for me.
Hot Rats right through to You Are What You Is really... Cruising With Ruben & The Jets is quite interesting for some Doo Wop too..
i used to hate his late classical-influenced stuff, but after listening to it with a more open mind it's pretty good. it may be cheesy and dated, but his choices of timbre for some voices are interesting. plus i love his unison lines. his pieces always have a distinct zappa sound. that is what every artist spends their career trying to acheive. he's a god.