Quote by micromass
I don't think you can ever go wrong with a differential equations class. Especially since you mention you would like to study this subject in grad school. Stochastic processes also uses differential equations a lot (or at least something very similar to it). So I would study this.
Whether to study ODE's or PDE's, I don't know. I'm leaning towards PDE's here, but I'm not sure how useful it will be for you later...

Well I was planning on taking at least one differential equations class out of the two. I was just wondering if it would be a better idea to take both diffeq classes vs. one diffeq class + complex or numerical methods.