Blur radius values vary widely depending on the effect you're looking to achieve.  I personally tend to use 0, since I like sharp, dramatic scenes. If you use it, don't use too much, between .5 to 1 is often enough.

As for min bias settings, between .2 and .3 generally give the best results. Sometimes I need to go a little higher, but never above .4, but I never go below .2, as self shadowing artifacts very quickly crop up.