For the purpose of a video blog, (ie youtube) there is little effective quality difference between the two, but if you are willing to spend the money for a camcorder, having the benefit of optical image stabilisation (if it has it) and manual white balance (so that colours aren't affected be differences in lighting) can make the difference in how good it looks. As far as editing goes, any software that can cut/paste and add text and image efx should be good enough for video blog use as long as it can be encoded small enough to make uploading it easier/faster. (a basic hack and slash editor/encoder can be found here:
http://avidemux.razorbyte.com.au/)
Nutshell:
webcam (I recommend this one
http://www.newegg.com/Product/Product.aspx?Item=N82E16826104087)
+cheap (and an autofocus model isn't too expensive)
+good enough video and audio quality
-white balance issues
-often jerky video if your computer isn't fast enough to process the video
-often has low quality microphone (lots of noise picked up)
-is a one trick pony in that it can't be used portably like a camcorder or the video recording in some mobile phones
camcorders (I recommend anything with OIS although that tends to be expensive)
+high quality video
+able to be used for other purposes
-cost
-microphone quality often isn't much better then in a webcam
-overkill for a video blog (who needs the option of hd res video?)
EDIT: another alt is a digital camera, most of them are good at recording video as long as a fast storage card is used. the pluses include being relativity cheap, most have manual white balance settings, optical image stabilisation, and having multiple uses. (ie taking photos) the big con is cost for a *good* model and it may not be able to zoom in/out during video recording.
