Since it hasn't been mentioned yet, Derpiboo.ru is the de facto heir to ponibooru, although it's not yet as all-encompassing. I personally am with the google crowd though.
Okay, here's the thing about the pony songs. They are super cute, and yet they're actually quite melodic and many of them are very good. On your first watch through, listen to them, cringe, and don't worry about it. Go listen to some remixes or something later, Eurobeat Brony and Living Tombstone make really good ones, and Imnotacleverpony made several excellent almost original remix pieces based on melodies from the show. Then go back later and listen to some of those songs again.
And I do remember Land Before Time. The original was superb and a wonderful childhood movie with some legitimate dark themes (Sharptooth was scary as hell when you're 6). All follow-up movies do not exist, there was only one movie and I refuse to hear otherwise.