I don't know how exactly quantitative I can get beyond 'small stars are bad' - I don't think there's a lot of collation of the necessary data. I can try.

• Stars bigger than ~1.2 solar masses (in the middle of spectral type F) would cook Earth-analogs before we had large amounts of multicellular life, though that might not be true for all theoretical lifebearing worlds.

• http://www.solstation.com/stars.htm is a fun source for known stars in the solar neighborhood as revealed by the Hipparcos satellite dataset. It might not be as rigorous as the datasets themselves but it's certainly easier to navigate. There are at LEAST 1400 stars within 50 light years of the Sun, only ~64 of which are solar type (spectral type G) and about ~46 of which are larger (F,A,B). There's a full 152 (or more! - out at 50 LYs some might be missed) K type stars that are smaller and longer lived than the sun in the same volume that are not smaller to the point of being M dwarf stars. Some of those stars might last up to 30 or 40 billion years, with any one planet possibly being habitable for a reasonable fraction of that time compared to Earth's up to 6 billion years. This does make me wonder if a large fraction of them are unlikely to spawn biopspheres for some unknown or underappreciated reason, or if we just got slightly 'lucky' in that we are in the upper quarter or so of stars that probably spawn complex biospheres in terms of mass, which actually isn't all that weird all things considered.

• One might expect longer-lived K-type stars to have longer-lived biospheres and have a higher chance of spawning intelligent systems, making that 'upper quarter' thing a bit more odd. I have no answer to this. I can randomly speculate though: Maybe planets 'run down' in some way over time in these systems over timescales slightly longer than the Earth has in our solar system before the sun cooks it. Maybe the brightening sun is closely balanced by Earth's cooling geosphere putting out less and less CO2 and other such gases over time and these processes wouldn't balance for as long in a system with a slower-evolving star, such that solar-mass stars are more closely tuned to long-lived biospheres than we expect. Maybe star mass has unappreciated statistical ties to planet types. Or maybe we have just hit on one of the random weird things about our biosphere that given there are so many variables that go into each biosphere you will find a few of that aren't necessarily important but are nonetheless there. With a hundred uncorrelated variables, you'd expect us to be in the 95th percentile of several of them...

• Maybe stars of masses that we see as only sometimes being flare stars is a case of individual stars occasionally flaring regularly and occasionally not over human timescales rather than different stars behaving differently over geological timescales - we've only been watching for a short time.

• Stars smaller than ~0.5 solar masses (M type, red dwarfs) need a planet to be so close in to get an Earthly amount of radiation (< 0.3 AUs) that they probably tidally lock. There's endless arguments as to if that's a no-no or not for complex biospheres and what it means for atmospheres and hydrospheres. They're also often flare stars.

• Red dwarf stars have a longer cooldown period from formation, which was done in our system pretty much during the planetary accretion stage, and might complicate habitability arguments.

...Conclusion: there's too many maybes here.

PS: I can't freaking wait for the GAIA mission dataset to come back, it'll be the greatest star map ever created by orders of magnitude...

ANOTHER EDIT: A lot of interesting discussion in the commentary of http://www.centauri-dreams.org/?p=9032 - looks like the limit of tidal locking for something with terrestrial illumination is closer to 0.7 solar masses.

YET ANOTHER EDIT: Another visualization of nearby star systems: http://www.atlasoftheuniverse.com/50lys.html