Just found a neat seed; aparently the seed pikachu spawns you in a giant jungle biome with a few patchs of naturally occuring pumpkins, bordering a desert, and a plains biome, with a very large open air ravine near the spawn point.
edit; it also borders a snowey taiga biome
Also; the ravine contains trees(or at least bushes), coal, iron, and a lava flow, there is also a large lava lake in part of the jungle which starts a small forest fire.
edit 2: another interesting seed is the seed "minecraft", which spawns you in a large open plain, but, you are within a short distance of another very large jungle biome, a snowey biome, a desert biome, a hill biome(or at least a jungle with a lot of large hills), and a swamp, in addidtion to the plains biome you start in with it(which contains a pumpkin patch within about 30 blocks of your spawn point)