I was thinking about this as well. My pre-med advisor suggested that taking time off has the following advantages:
1) You will have more time to devote to your applications. You will have more to put in your applications as well (extra year of research, etc)
2) You get to include your senior year grades in your application, which, if you have, say, a 3.4, may not be a bad thing.
I guess my questions - along with original ones raised by blazinfury - are:
1) Is it common for MD-PhD applicants to take time off? There's a significant number of premeds from my school who have taken time off, but most MD-PhD applicants have gone straight to school. My PI suggested that this probably reflected the fact that MD-PhDs were super eager individuals who were absolutely certain what they wanted to do, and did not mind diving into school work and academics without a break. My concern is, will a student who has taken time off appear less dedicated than a student applying during their senior year of college?
2) If one does plan to take time off, is there something he/she should try to do/ should not try to do during that extra time? Is doing something research related absolutely vital (provided the applicant has the usual amount of research experience)? I am thinking of working at a biotech firm/private firm (in a research related capacity) to see whether I like it or not. Is that a feasible plan, or is there a possibility that I might get blacklisted by academia for venturing into industry?