1) Gun Crazy (1950) - Tamblyn's breakthrough role as a child star was in Samson and Delilah but I go for this, because it's a more brilliant film and tamblyn's more believable as a young John Dall than as Saul (Samson is quite fun, though)
2) Seven Brides for Seven Brothers (1954) - a lot of MGM musicals were losing money around this time but this was a smash hit, in part due to its energy and colour, including a great turn from Tamblyn - this turned him into a dancing star. The story line is inherently dodgy ("let's abduct some women").
3) The Fastest Gun in the West (1956) - at MGM Tamblyn developed a niche playing keen teens in support of older actors, such as Glenn Ford - this is a good Western, and they put in a dance number for Tamblyn which Ford (one of the biggest divas of the 1950s) tried to get removed
4) Peyton Place (1957) - a triumph of adaptation to get this past the censor and make it cohesive (I've read the book)... the film is a lot of dodgy fun, including Tamblyn who is genuinely good as a weird teen (he turns "normal" in this which he didn't in the book but he should have played more weirdo roles)
5) Tom Thumb (1958) - charming musical fantasy with Tamblyn ideal in the title role.
6) High School Confidential (1958) - terrific fun with Tamblyn doing 21 Jump Street, as an overage undercover cop battling dope pushers, the seduction of Mamie Van Doren, and beatnik dialogue... this was a big hit, and other Albert Zugmith films for MGM weren't... maybe because they didn't star Tamblyn, who knows, he was in a lot of hits around this time.
7) West Side Story (1961) - Tamblyn was a little old to play Riff but he had tremendous energy - no George Chakiris but better than Richard Beymer, shall we say.
8 ) War of the Gargantuas (1969) - in the late 60s Toho would import American stars for their films (usually Nick Adams) - this had Tamblyn, looking stoned and ad libbing dialogue (as he would in his other cult classic, Satans Sadists) - lots of fun.
9) The Haunting (1963) - genuinely good film showing what Tamblyn could do - he didn't like acting that much though and went bohemian soon after.
10) Twin Peaks - Tamblyn makes a comeback as the eccentric Dr Jacoby, totally fitting in Lynchian world.