I'm pretty sure that the first real guitar solo that I ever learned was the one from Californication. I was probably drawn to the song by the video. It came out about a year before I started playing guitar, at a time when all of my free time was spent gaming (and watching Reboot), so the video game theme of the video had me intrigued every time it was on TV.
Learning any solo seems like a daunting task when you're a beginner, but this one actually felt doable. Mr. Frusciante wasn't doing anything crazy. He gave every note room to breathe which gave me time to keep up.
Sidenote: Flea is one of the main reasons why I own a bass.