As an actual musician, songwriter, and guitarist, it's really hard to not see Cash as an inspiration. In fact, recent viewings of "Walk The Line" finally have me deciding to take my songwriting to a different level. The way he writes songs and the meanings behind them has inspired me to have each song I write come from the heart. Some of these crappy bands who think they're playing good, wholesome music need to really listen to Cash and find out the true meaning of songwriting.
I think every aspiring musician needs to look at Cash's career as a sign of hope. If he could go from nothing to anything, we need to think we can too. Also, if you look at how he plays the guitar, all he's playing are chords. Sure, his guitar licks got a bit more intricate as his career went on, but it shows that your song doesn't need an impressive riff or face-melting solo. If you can tell a story with the song, then who cares what the hell your playing?