I have based my oil and filter choices on these 3 articles below, plus a few others, along with testing different oils and seeing which ones caused me to miss or not miss shifts, or made the clutch feel better or worse to me.
My personal choices are not all that important- different people have different engines and different feet to shift with and hands to pull in the clutch with, but these articles are a good beginning for a beginning rider.
You may choose the dealer selected oils and filters to try to keep your warranty in effect, but legally anyone can change the oil and filters and keep a record of them while following what the owners manual requires, and the warranty should be honored, especially since it is so rare for a major engine problem to occur during the typical one or two year warranty period. For an extended warranty, make sure you read all of the fine print for it before buying it:
http://www.vfrworld.com/tex_vfr/tech/oil.htm
http://www.calsci.com/motorcycleinfo/FilterStudy.html
http://www.sportrider.com/tech/146_0310_oil/index.html
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