I'm a chem major - actually a dual major chem and math. I hated bio, too... but i think it was mostly 'cuz my gen bio prof sucked. The upper division bio classes i took were easy and the prof was great.
I LOVED my upper division chem classes. being a math major helped a bunch, so pchem was actually easier for me than ochem. advanced lab was AWESOME. Instrumental analysis was no math at all, and really fun. Got to play with all those instruments that you look at and wonder "what does it DO?" I gotta admit, biochem was really hard without the bio background, and it sucked the life out of me.
All in all, I would've had a higher GPA if I had been a bio major. However, I definitely wouldn't have learned as much that I was truly interested in learning, and a bio major definitely would not have challenged me. I'm very happy having been a chem/math major. BTW: To do well in pchem, befriend a math major person. Alternatively, take complex variable calculus and abstract algebra (aka modern algebra) - those will help a bunch.