Personally I couldn't care less about finding microbial life. I want to find animal-sized life or heavy vegetation. That Mars might house single-celled life does nothing for my excitement.
Finding any life outside our planet would be a huge discovery; even if it's billions of years away from growing legs, we could learn so much about life in its early stages, which could answer some big questions about our own evolution.
I say we land there with humans, spend a few decades checking the place out, then begin with the terraforming.
I guess it's a function of cheap transport to LEO. If we get that, other things will follow. Go Space X!
I do not think terraforming need be terribly expensive, incidentally. We already map a great number of asteroids and comets out of awareness that if a sufficiently large one were to hit the Earth its impact would be devastating. Our best understanding at present of how to deal with the possibility of such an impact is to give the item a slight nudge that will alter its trajectory during a non-terminal interaction with Earth's gravitational field. We have already matched speeds with and made very close observations of asteroids, and our observational abilities are constantly improving. So to begin the work of terraforming Mars, I would begin looking for asteroids with large quantities of ice (or ammonia or other appropriate compounds) that are likely to intersect closely with Mars' orbit, and give them an encouraging nudge.
It annoys me that since the two rovers we've sent so far have worked so well, our response is to spend years developing a New and Better Rover at great expense, rather than launching launching a large number of rovers that use the existing design which is already known to work, and which can be done without any additional research whatsoever.
When we've only got one example and it's us, our estimate of the probability of life evolving on a given planet (given suitable conditions) could literally be anything from 100% to any arbitrarily low number you might like to think of.
If we check two life-plausible planets and find separate life on both, the probability is suddenly way biased towards the high end of the scale. (A statistician can figure that one out for me.)
In some ways, modern life does leave us out of touch with the complexities of the world and nature.
Rice was a lot more labor intensive in that it required more time in the field per food-for-one-person than wheat. It also doesn't store as well nor have bumper crops. So, if you have a bad year, it's hard to have a buffer with which to get by. As a result, the vast majority of the population had to get over themselves, cooperate and comply with spending most of their lives taking care of the rice or else people would starve. Troublemakers who did not cooperate were putting everyone else in clear, near-term risk and were dealt with harshly.