Natural cotton doesn't stink as much. Synthetics are great for wicking and heat transfer, but you do pay a price. Pick yer poison. Maybe on days when you have meetings, stick with cotton.
+1 on the vinegar. Another option is to soak your clothes in a vinegar-water solution before washing them.
This page says 1/2 cup added to rinse cycle helps decrease odor.
I've also heard that sunlight (i.e. hanging clothes outside) acts in much the same way as bleach to deodorize and kill bacteria on textiles. Of course, if that were entirely true, we wouldn't stink when we were riding our bikes out there in the sun ...