I went for the second bachelor's approach, mainly because the school I was at didn't have a formal post-bac program and it was the only way I could get financial aid. Because it was the same institution I got my B.A. from, all the original core classes (e.g., english, humanities) applied to the second degree, i.e., I wouldn't have had to retake them. This allowed me to focus exclusively on science courses. Once I had my med school prereqs out of the way, I just stopped taking classes. I haven't received the impression from any adcoms that this is unfavorable...my impression has been that all they care about is that I completed the prereqs, I took the science classes at a decent university, and that I had a full load of science courses at the time.