Well if we've got to go faster...
As others have commented I agree that nuclear thermal rockets are the solution here. They'll get you to Mars faster than the six-month journey offered by chemical rockets. Sadly, I doubt we'll see a NERVA-type rocket in operation anytime within the next 20 years or so.
The public will hear, "...blah blah technobabble something complicated NUCLEAR STUFF IN SPACE blah blah..." and are highly likely to freak out leading politicians to block the use of nuclear thermal rockets despite the fact that THEY OFFER TWICE THE PERFORMANCE OF CHEMICAL ROCKETS.
On the other hand, has anyone considered a solar thermal rocket? Much greater performance than chemical rockets, no scary bugaboos, and in the Inner system at least, quite a practical method of getting around.
Of course it'd take 10 to 20 years of research to get the kinks out but hey, we're not going to Mars in that much less than that.