Research in pure CS is likely going to be math oriented. Do you like the algorithms and proofs in your classes? Do you like them well enough to do them for a nice fat chunk of your life? Do you like them well enough to go into significant debt (unless you have bank already)?
More important than that though: Is there a particular subject within CS that you are INCREDIBLY passionate about?
This is not true. There is plenty of PhD work being done in things like AI, distributed systems, databases, programming language design, programming language runtime design, and many other topics that are not mathematical.
There is plenty of work involving math, if you like, but there is a lot more to computer science than linked lists and finding strings inside strings.
I'm going to defend my Ph.D. in December. I agree with the parent post. Check my profile for my academic page, which has my publications. I do research related to systems for high performance computing. Not much math. Mathematical reasoning and understanding is needed, but the research is not math.
Really? I can link you to about a million CS papers that do not mention formal math. And incidentally, this work is easy to apply directly to my day-to-day work as a practicing programmer.
(Some would say that means it's not academic enough... but you get the "Dr." title, so...)
More important than that though: Is there a particular subject within CS that you are INCREDIBLY passionate about?