It actually is a great idea to know more than one instrument, even if it's just guitar and bass. I find it gives you a different perspective on how to write/arrange a song.
What else do you have in that studio corner?
I totaly agree. I have different guitars for different styles and sounds! Mandolin, Dobro, accoustic guitar steel and nylon, two strats, one Telecaster and Epi ES335. I only miss a Les Paul 58