What's the music playing in Naruto Shippuden episode 1 when Naruto and Jiraiya are walking through the forest?
There are a large number of soundtracks in Naruto that were never released officially. For these songs, sometimes you can find an unofficial version online. Fans construct these versions by splicing together audio samples from various episodes, so if there aren't enough samples, the audio can be partially distorted due to voice removal manipulations and the like.

For this particular track, it seems that there was a particularly good sample from Shippuden episode 343, so no splicing needed! It's been uploaded to YouTube titled as "Peaceful Theme" and also "Konoha Peace".