If you decide to play both, please don't fall into the trap I've seen alot of guitarists fall into.

Don't play the bass like a guitar!!!!!!!!!!!!!!!!!!
The bass in music serves a very specific role. Learning to play both means recognizing both roles and not crossing over.

When I see a guitarist playing bass outside the proper role, it makes me want to puke, and then punch in his face. Yes I feel this strongly this.