cappy..i'd make sure you can get a job after the degree.. I wonder what you will be able to do with a BS in biology.. around here theres a ton of pharmaceuticals so it would be good.. but i wonder what its like where you are..
computer science will get you a job anywhere.
I currently have a job in the Computer Science field without the degree. My experience in the field is extensive, so I pretty much get any job I apply for. Recruiters are always calling me to see if I'm interested in other positions.
The only real reason I took classes on this subject was because JW's convinced me that it would be easier to support myself pioneering as a programmer / designer. I soon found out that there weren't many decent part-time programming positions out there.
Also, Computer Science will get you a job in any major city, however the jobs in the rural areas (which I prefer) are scarce.
Unfortunately, I don't truly enjoy this field of work. I find joy in getting things done and accomplishments, but I don't really like what I do.
My ultimate purpose in going back to school isn't really to further my career, but to study something that I love.