One of the reasons that I NEVER go to Walmart is that their carts are so insanely small that I can't fit enough in there each trip (especially if I have at least 2 kids with me), and end up having to make another trip to get the rest...I think it is deliberate to make people come back more frequently.
Target--that's my store. Even if I don't have any kids with me, I still get one of those supersized carts with seating for 3 kids--gives me a TON of space to put the items I need, and I don't have to back for a LONG time.
I almost never go to Costco anymore--when I do, I focus on the frozen goods, stock up, and don't go back for 2-3 months.
I grocery shop at Ultra Foods because it is MUCH cheaper than Jewel & Dominick's, and then I get my produce at Westbrook (on 63rd St)--VERY cheap fruits/veggies, or if I want organic items I go to Whole Foods on 63rd St in Willowbrook.