Go and look at the rode videomic and the videomic pro. The original videomic could be had for around $100 and it's perfect for those who want to walk around while shooting. Now I don't know if it will work for you as it does for me, but I own 2 videomic pros and they don't seem to have a problem. They plug right in to my 60D's and work every time.
But as stated above lav mics are also a really good option for capturing ones voice. But check out the videomic. I love it!
Hope this helps![DOUBLEPOST=1394464278,1394464045][/DOUBLEPOST]Don't go with any USB mic if you want to be able to get up and move around with your camera. But if you sit down at your desk and shoot most of your videos in one place (not moving a lot & can have a computer close by) than a USB mic might be something to look in too.
Also if you get a USB your going to have to record audio in a software in your computer (audicty free audio software, works great) and then pair it in post in some sort of movie/ video editer.