If you are a very mature and responsible high school student very interested in medicine/science, I would highly RECOMMEND a 6, 7 or 8 year combined program. I am myself a product of a 6 year BS/MD program and loved it. It is so nice to be young, done with college/med school/residency at the age of 26 and have time to enjoy life. I have been working for 2 years, am married, have a house and am able to really enjoy my work and married life. In the meantime, my friends who took the normal route are just getting into residencies. They are still living out of dinky apartments, making ends meet and in general just "trying to get done with it already". There is nothing wrong with a traditional path...it just takes longer and as it is, medicine is a long, long road. Most countires don't have undergrad requirements at all...they just get you straight into med school out of high school. A traditional 4 years of college is necessary for someone who needs time to mature and see what else is out there...which is probably 95% of the world.
So I'm not to saying that the 6 or 7 year way is the right path for everyone. It is difficult and you have to be super dedicated. You may have to work through summers in undergrad unless you have lots of AP credit. But it definitely has its PROS - mainly avoiding the hassles of having to constantly make your CV look stellar during college by doing activities you may not really care about, having to work your a$$ off for MCATs (most 6 year programs have minimum or no requirements for MCATs), and of course, getting done early. Believe me, its so nice to be able to enjoy married life after finishing residency instead of constantly juggling school, work, and life. Some people even have to juggle kids into this equation and I don't know how they do it.
Anyway, my 2 cents.