I was an engineering major before I went to med school. I'll approach this on two levels.
- Will a Bachelors in CS be a plus for admission? No matter what your major, you have to meet the prerequisites and make good grades. Beyond that, it can be the luck of the draw on the admissions committted when you apply. One place I applied, the Dean of admissions had been quoted in the school paper as saying medical schools should not accept engineers. I didn't get in there. When I was interviewed at the medical school I ended up attending, the committee ended by asking if I had any questions. I told them about the Dean of Admissions at the other school, and asked what they thought. They said they thought it was strange, and they could recall engineering grads that were top notch med studets.
- Will a Bachelors in CS be a good background for medical school? I think so, particularly if you take courses in health informatics. Computers are an important tool in medicine, and are becoming more so all the time. People who come from the more common biology or chemistry backgrounds can find more overlap with the basic science courses in medical school that a CS major would. This makes it easier in the short run, but in the long run, understanding computer science will be a plus.