I've been using these Cactus Picks. Good grip, long lasting, and cheap. See the link or also available on ebay in smaller lots. Just search for cactus picks.
from wiki: Tortex is a brand created by Jim Dunlop, but tortex picks are made out of a plastic called delrin that was created by DuPont. Dunlop's Tortex and Delrex picks are both made of delrin, but have different surface coatings.
Everly Star Picks - I used Dunlop 1mm (and still do) for YEARS until I discovered the Everly Star picks. It feels exactly the same as a Dunlop Tortex but, has a star cut out in the center to assist with the grip. I REALLY like.