While I maintain that on the whole, 'Secret of NIMH' is probably my favorite Bluth film, it seems to go without saying that 'The Land Before Time' is the most popular. It has happened very under the radar, but this 1988 children's classic has spawned a grand total of 13 straight-to-video sequels; the last one coming out as recent as 2016. It's really cool to know that this has actually lasted so long, and that there's still an audience for it somewhere.
I would suggest that this is the Bluth film I feel most nostalgic for, however. This is the one that takes me back to my childhood days, and it was somewhat surprising how much of the dialogue I remembered, as I quoted along while watching with a big grin my my face. I can't deny that this viewing was fun for me, as it had been quite some time since I saw it. But I remembered the love I had for it as a kid, watching it time and time again with friend after friend because, hell, we all liked it. For some reason, dinosaurs were a huge thing in my childhood - and I'm talking years before 'Jurassic Park' came along to perfect it for us.
The film first introduces us to the likes of Littlefoot the "Long Neck" (Gabriel Damon) and Cera the "Three Horn" (Candace Hutson), who become separated from their families during a bad earthquake. In the process, Littlefoot also tragically loses his mother (Helen Shaver) who, beforehand, was leading him and his grandparents to The Great Valley; a lush land full of food and water, necessary for their survival. She reminds him how to get there, and the poor kid has to venture there alone. He does, however, eventually come across a few friends who join in the perilous journey; apart from Cera, Ducky the "Big Mouth" (Judith Barsi), Petrie the "Flyer" (Will Ryan) and Spike the "Spiketail" (Frank Welker). Along the way, they must face many obstacles, including a vicious T-Rex named Sharptooth (also Frank Welker).
One thing the film never seemed to lose for me was its overall sense of wonder. Composer James Horner along with the animators on this really do manage to take you away to this almost magical land of dinosaurs. Admittedly, the animation can certainly look dated here and there, but I'd urge you to pay closer attention to the backgrounds and environments than the characters, themselves. It does a fantastic job with scale, using very little. A solid reference point would be when Littlefoot's mother introduces him to "tree stars", and brings one down to him with her long Apatosaurus neck. In the meantime, Horner's score does a great job at setting the mood, whatever the case may be.
'The Land Before Time' was a great way to introduce dinosaurs that would speak to kids, and teach about love, death, teamwork, and even friendship among different races. There's a whole concept in here where dinosaurs stick to their kind because they're all different, but the journey includes five different breeds banding together to get to their common goal, as well as bring down a common enemy. And, get this, it does everything within the course of just over one hour. It's a very easy movie to sit down and watch at random, which is perhaps why I probably managed to wear out our VHS recording of it. Side note: recorded on the same tape was THIS half-hour claymation dinosaur musical special, starring 1980 Fred Savage.