i currently work at a small biotech firm (founded in '02) and the answer to your question, is med school good TRAINING for biotech startup/VC, is no.
there are loads of routes you can take but the key to getting into VC would be connections. i have heard my CEO and my boss (VP of corporate/commercial development) talk about this career path many times and it's really about who you know in VC. this component will be critical no matter where you're coming from.
that said, if you had asked, is pursuing an MD degree USEFUL for pursuing a career in biotech/VC, then i would say yes. i'm not sure if it's better or easier than pursuing a PhD (definitely not easier, from the number of PhD people i've talked to in my company), but it's certainly a good path. our VP of product development came straight out of med school (UTSW) as one of the first employees (#3 i think). but then again, our VP of research was a founder and he's a PhD.
i also think it depends on what you want to do in a biotech firm. if you want to be involved in the financial aspect, then i would say an MD or PhD is not as useful. you need to have that business experience in addition to your scientific knowledge. this said, if you majored in a science during college, i would say this could potentially fulfill your science-knowledgebase requirement and i would suggest simply pursuing an investment-banking or consulting route and go to a top business school where you could acutally connect with VC/biotech people.
my boss (who graduated wharton) said that only 2/3 people actually get into VC from any of the top business schools (say, 2 or 3 of the 400 people at wharton who want to go into VC) so it's clearly very competitive. perhaps getting an MD and going directly into business and then getting an MBA on the side where you can make those VC connections would help you stand apart. or, you could try to join any of the large pharma companies and simply work your way up for a bit and then try to join a start up. many of our directors and VPs are from large pharma.
if you have any questions about what it's like in a startup, feel free to PM me.