I have to say, compared to Japanese convenient stores ("conbinis"), American ones just can't really measure up. That is one of the little things I like about being over here. You can pay bills, buy tickets for sports events, concerts, etc, buy many kinds of liquor, household supplies, and if you buy something that needs to be heated, the clerk will personally microwave it for you.
And tell me this - can you buy 4 liter jugs of liquor in a convenience store back home? I think not (although someone may correct me - maybe I just wasn't looking hard enough).