Anyone that has been to Hawaii knows about ABC stores. I was stoked when I discovered that there were 2 ABC stores in Desert Passages shops in the Aladdin Hotel (now Miracle Mile/Planet Hollywood) a few years ago. Now every trip to Vegas guarantees at least one stop here.
The great thing about ABC stores is that you can get pretty much anything you need while on vacation for a decent price. They have a ton of souveniers - magnets, pens, calendars, tees, glassware and whatever else you may want to bring home. They carry your standard snacks but also carry snacks that cater to their Asian clientele (wasabi peas anyone?). Plus they have a bunch of Hawaiian snacks - cookies, popcorn and macadamia nuts galore. This is also the best place to get Las Vegas themed Hello Kitty stuff - post its, cell phone charms, pens, etc.
And they have beer, wine and liquor. One stop shopping, for sure.