Ask people who read blogs who there favorite is and why. Influential to one person may not be influential to another. Right now there is only one blog that I go back to on a regular basis but I know my friends would not be interested in checking out a blog on blogging.
I have given up blogging for a while, but my blogs earlier used to be very popular. What kind of subjects are you looking at? I used to have a dating blog which got hundreds of hits and comments per day.
You can always check social bookmarking sites. Take Technorati for example, the more authority the blog has the more people see it as an influence . . .
A blogger about blogging or on other subjects? If you meant on blogging check out Darren Rowse Glen Allsopp Yaro Starak