Well, this is my opinion:
Great Valley AdventurePeaceful Valley: I'm fairly neutral when it comes to this song. I don't hate it, but I don't think it's the best either. I prefer the ending version to the start one though. It looked to me like the characters weren't even singing anything, they were just walking around with their mouths hanging open!
Eggs: Haha, this was quite a catchy and fun song. I really like villain songs, and this was a great song to show Ozzy and Strut's intentions.
You're one of us now: I never really gave it too much thought. I actually don't really find this one very appealing, I would usually skip it.
The Time of the Great GivingWhen You're Big: I think this song is fairly good for what is it, but I really don't like Hyp's singing, and the other bullies don't make up for it, either.
Standing Tough: I gotta admit, I actually really like this song. I also enjoyed how the other adults were moving their heads to the beat, it was quite amusing.
Kids Like Us: This was a really nice song. As a teenager, going through that stage of becoming an adult, but still being a kid, actually really speaks to me about other teens. They're still kids for the time being.
Journey through the MistsGrandma's Lullaby: This song is actually higher up on my list than most. I think Linda Gary did a swell job, and it's unfortunate that we never hear Grandma sing again. I actually watched this movie and listened to this song the day after I found out that my grandpa had passed away, and it taught me that these things were a part of life, so this is a song I have always kept close to my heart.
Who Needs You: I loved this song's wittiness, and it sounds just like me two years ago when I kept getting into arguments with my best friend, haha!
It Takes All Sorts: Eh, this was the worst of this film. I didn't like Ali's singing voice that much.
The Mysterious IslandBig Water: This was quite a catchy song, and I always find myself singing along to it. I enjoyed it.

Always There: Oh my treestars... I was bawling at this one when I watched it again after so long. Hearing Littlefoot singing about his mother just made me tear up big time. This is by far my favourite of the movie, and is also high up on the list.
Friends For Dinner: It's quite fun, but Chomper needs singing lessons. Really. His singing was pretty bad.
Secret of Saurus RockLegend of the Lone Dinosaur: This one is one of the songs that annoyingly gets stuck in my head when I'm trying to concentrate on something, which is why I try not to listen it to it that much. Saying that, it's not a bad song, and it's quite catchy too. It's not my favourite though.
Bad Luck: I didn't really see the necessity of this song, but I enjoyed it, mostly because of Spike's scatting. XD
On Your Own: To be honest, I never really gave it much thought. It's actually quite a nice song.
Stone of Cold FireBeyond the Mysterious Beyond: I actually really like this song, it had quite a sense of wonder and mystery to it.
Good Inside: It was worthy of a "meh" from me. I never really liked it, personally.
Very Important Creature: Again, it's not my favourite, but for a bad-guy song, I really like it. It's a song where you see what everyone's real intentions are.
The Big FreezeThe Mad Song: I absolutely love this song! I don't get mad very often at all, but when I do, this song describes it perfectly.
Family: This song is really beautiful and heart warming. It was also nice to see Ducky's mom have a song.
The Lesson: I never really had much time for this one. It's not bad by any stretch, but I just don't listen to it that much. I'm not entirely sure why, actually.
Journey to Big WaterChanson D'Eunnui: Sums up my Sunday evening. XD
The only thing that bothers me is in the animation sequence. What the heck was with that log?!
Imaginary Friends: It's pointless, unnecessary, and it sucks. I really do not like this song, and I don't really see what the idea was.
Big Water Reprise: I like that they referred to one of the earlier sequels, but aside from that, it wasn't necessary, and the singing wasn't great either.
No One Has to Be Alone: This is one of my favourites, and is by far the best of this movie. Whenever I feel lonely, I always listen to this song (In most cases it's the Donny Osmond version), and I feel 1000x better. It's a really beautiful song. Both versions are equal on the awesome scale in my opinion.
The Great Longneck MigrationAdventuring: Love it. I couldn't stop singing it when I went on a trip to stay in a log cabin in a really lovely forest. It's one of those catchy and fun songs and thankfully it doesn't get stuck in my head and annoy me too much, either. XD
All of the TV series version, though, I hated. It was just repeated over and over again and I really just didn't like it. I only actually like the movie version.
Me and My Dad: Eehhhh... no. I didn't like this song. I like the animation that went with it, but the song itself was way to high pitched for Littlefoot's voice. 8D
Bestest Friends: Beautiful, simply beautiful. Need I say more?
Invasion of the Tiny LongnecksCreepy Crawlies: A very comical song courtesy of the adults. Oh, Mr Threehorn, here we go again. It's definitely an enjoyable song.
Girls and Dads: Pretty good, but those singers in the background... kinda creeped me out, actually. They just appeared from nowhere! But, Cera and Lizzie actually do make a good duet.
If Only: Hmm... again, I'm neutral with this one, but it was nice hearing Grandpa Longneck sing.
Great Day of the FlyersOne of A Kind: I actually don't think this song was too bad, but I think Petrie is better off not singing.
Things Change: This was a pretty powerful song to me. I really liked how it showed Cera's feelings and then changing her mind and thinking that this wasn't so bad after all. It was really nice.
Flip Flap and Fly: It may have been goofy, but I loved this one. I don't what is it about this one, but- wait, did those judges just throw a hatching egg in the air to fall to it's doom? What?! It was still really fun, though.
Wisdom of FriendsSay-so: Eh... it's another one of those ones that got annoyingly stuck in my head, so I try to avoid this one.
Yellow-Belly Bounce: Same as the one above. It went on for a while, too, which didn't help.
How do You Know: This is probably the only good thing about this film. It's quite a nice song, it's just a shame the rest of the film ruined it.
Last but not least:
The Original Land Before TimeI'm not going to review each track, because they were all spectacular! James Horner really outdid himself with this score, and "If We Hold On Together" was a beautiful song. I really enjoy classical music, and this is by far my favourite movie score. Well done, James Horner!