I'm going to repeat a few things already listed, but here goes:
Bottled water - 35 pack of 1/2 liter bottles for $4.69 = 13¢ a bottle. Can't beat it.
Kirkland tuna - def. better quality, makes up for little/no savings over grocery stores
Kirkland pecans (for holiday baking)
Kirkland Vanilla
Stacy's Pita Chips
Arnold Sandwich Thins
iTunes gift cards - four $15 cards for $55, sometimes as low as $48 (I always stock up when I see this promo)
Kirkland batteries (AA 48 pack is $12.50)
Kirkland Cetirizine (Zyrtec)
Kirkland Ibuprofen liquid gels (when they have them)
Individual tubs of Sabra hummus
Fage yogurt tub
String Cheese
Grape tomatoes
English cucumbers ($3.39 for three - usually $1.50 - $2 each in the grocery store)
Fresh Raspberries
Lemons
Heavy/Whipping cream quart - $2.49
Shrimp cocktail platter - a lot of shrimp for $9.99. The frozen shrimp is also good, but I'm usually looking for a quick supper, so I buy the predone.
Ciabatta rolls
Rotisserie chicken (or the rotisserie chicken salad)
Pesto sauce
Babybel cheese multipacks (cheese in general is almost always a good deal)
Kirkland 33 gallon black drawstring trash bags & 13 gallon white kitchen bags. Excellent quality, great price.
Flowers
Paperback books (maybe cheaper on
Amazon, but I like instant gratification

)
agreed that electronics are usually a good deal, and the extra warranty is nice
Gift cards can be a great deal
Multipacks of white hand towels & face cloths... if they get grungy, they become rags.
Microfiber towels (in the car care area).
and my new favorite...
AMC Gold Movie tickets - two for $15.99, and can be used on first run movies, even when the listing says "no passes"
lol - and this is just what I buy on a regular basis. Coupon values and special purchases are a whole other matter.
The meats and fish are excellent, but I'm one person, and usually can't use that quantity before it gets freezerburn. But I've bought for parties...
Oh! in the fall/winter, they had Kirkland sheepskin boots (like UGGS) for $35-$40