Current I have one blog with blogger. I eventually want to establish 4 blogs of different niches. Fishing, Nutrition/fitness, Comedy, and Product Comparisons. Should I create a new blogger account for each blog? Should I create a new twitter and social bookmarking accounts for each blog?
Yes you should.
People will read your blog because they are interested in one topic, and will become disinterested if they are constantly updated with things they don’t care about (your other topics).
yeah go nuts, create as many multiple personalities as you can, keeps life interesting.