My favourites are:
ashf00t
Awesome, cute and kind-of tom-boyish girl who has been riding a 2007 GSX-R 600 since she first started riding. She likes singing and has just started riding track-days.
Sample video:
Link to original page on YouTube.
Mordeth 13
Funny, outgoing and happy-go-lucky Canadian guy who has been making videos for a long long time. No introduction really needed.
Sample video:
Link to original page on YouTube.
808yewtube
Representing for the pre-gens, she's a self described "Japanese Gurl on a Japanese bike" who lives in Hawaii. She has a very peaceful and happy temperament that will boost your qi levels as you watch her videos.
Sample video:
Link to original page on YouTube.
svengalie
A straight-talking English lad who rides sport bikes and mx bikes. Likes gadgets and playing pranks on people - he sometimes combines the two. Worth watching.
Sample video:
Link to original page on YouTube.
Note: ashf00t and 808youtube do normally talk in their videos.