Rob, I posted this on the editor's page:
128. Rock Around The Clock (1956) - Bill Haley & His Comets
This is not a legitimite album. It's a collection of songs that had
all been out on singles before the album was released. It's really
just a "Best Of" collection. I'd get it off of this list, it won't be
on the "Greatest 50s Albums" list.
Every song on this Haley album had been released on a single before 1956. It's just both sides of six of their Decca singles, ands it's really just a 12 inch version (12 songs) of an earlier 10 inch album (8 songs) by the group, called "Shake, Rattle and Roll." Even the 10 inch album was a 1955 release that was just a collection of previously issued singles, mostly from 1954.

Coincidentally, aside from this Haley item that is not really an album, we agree on the top 4 albums of the 50s, and they will be on the 1950s albums list in the same order that you have them in here.
1 ¦ Elvis Presley - Elvis Presley
2 ¦ The Chirping Crickets - Crickets
3 ¦ Here's Little Richard - Little Richard
4 ¦ Bo Diddley - Bo Diddley
Although the Bo Diddley album is very iffy to be considered a legit album. It contains all tracks that were on singles with two of the songs that seem to have been released as a single around the same time as the album was released. The other ten songs were all released on singles either months, or up to two and half years, before the album came out.