If your budget allows, I would try to pick a bike up from a bike shop vs picking one up at a department store--you'll be glad you did! Getting a decent hybrid at a department store is going to run you upwards of $200. The bike will not be professionally built, the components are going to be from the bottom of the barrel, etc. Spending a little more will get you a professionally built, high-quality bike that will last you for many years. That being said, if a department store bike is all you can afford, then by all means go with the department store bike. Your budget will ultimately prevail. You could always sell the bike next year and upgrade if you find that commuting is something that you want to continue doing.

With that being said, if I were to buy a bike for commuting today I'd go for the Giant Escape City. It's a decently equipped bike, it has a rear rack, fenders, etc. As mentioned other companies make similar bikes as well. I definitely agree that you're looking for a hybrid.