Last year Courtney and I realized how many plastic bags we were bringing home every week from the grocery store. We re-used them for random things, but we couldn't get rid of them fast enough. Finally, this summer, we found a beach bag on sale at The Gap, and started taking that with us to the market and grocery store. The difference has been phenomenal. These bags are such a nuisance and detriment to the environment, and the stores seem ready and willing to give you hundreds during each shopping trip. We now have two re-usable cloth bags (and another set waiting for us on the mainland) that we use for every grocery trip.
Ireland has recently imposed a $0.33 fee for each plastic bag, and this New York Times story tells about its impact - they saw a 94% decrease in plastic bag usage within weeks.