the rode vidioe mice are popular, same with the sennheiser mke 400.  I think rode just made a new small mic for dslrs that is supposed to be pretty good, but it might just be because it is small (and may not need batteries).  Beyond that, I think some people use the rode ntg-2, but this is an xlr mic which amy not be what you are looking for.  All of these listed are shotgun mics, if you want to use lavalieres or a different set up, I'm not as familiar with those.