I have been taking Culturelle for a few months- it really does seem to help, and the cheapest place I've found to get it is Walmart.
During and after my last round of Cipro, though, just the Culturelle and yogurt twice a day or so weren't helping as much as they usually do, and it was taking a while for my system to get settled again. I bought some unflavored and unsweetened Kefir, which has 10 different probiotics in it (I bought mine at Whole Foods, and I think Publix has it too- dairy section <img src="i/expressions/face-icon-small-wink.gif" border="0"> ) and have been adding a tablespoon or 2 of it to my yogurt (straight, flavored Kefir doesn't sit well with my stomach for some reason ???, but yogurt I could live off of, lol), once or twice a day, and now am feeling better and back to "normal" after about a week <img src="i/expressions/face-icon-small-wink.gif" border="0"> .