Sources for Starter

Carls - (see Samartha's reply) This one works great and tastes good,
until you accidently turn the oven on while your only jar of starter is
in the oven. Great price.

SDI - I always had good results with the San Francisico starter - the
best flavor was on the first few loaves then petered out. Their high
price and poor bedside manner is a major turn-off. I use the Bahrain
starter which is very vigorous (thanks Slim) and used the Finnish
starter which had an unusual taste probably intended for heavy breads
that don't talk too much (Finnish humor)

Mr. Baker - www.yankeeharvest.com. - Great starter. Very strong riser.
Average flavor - not predominately sour. Good price!

SourdoughBreads Starter - www.SourdoughBreads.com - Similar to Mr.
Baker. I did not achieve very noticeable sourdough flavor, but was
excellent riser. The lady is fast on the mailings. She could charge
less.

And last but not least,

Acme Starter (from the Berkeley bakery) - It is the one starter (for
me) that makes a loaf that when I open the bread bag I smell sourdough
instead of country white bread. It is a marginal riser at best but I
love the flavor. Other people have had mixed results, but it's free for
the asking.

Ed Bechtel