I think the 'bifidus digestivus' and 'bifidus regularus' bacteria are a bunch of marketing bullshit. As noted by previous posters, they basically took some Bulgarian bacteria, renamed and trademarked it, and marketed it.
I do believe in the benefits of probiotics, although I think they are pretty low unless your body is under specific conditions that might kill all or most of the flora in your intestine. Like if you took antibiotics. Intestinal bacteria are very important, and you gotta replace it somehow if it dies off. In fact, some doctors are seriously suggesting that shit is an organ, just like your lungs and heart and whatnot. They think it is necessary for human life and if your intestinal flora is damaged, in some cases they are seriously suggesting poop transplants. Seriously, some doctors are cramming other peopless shit into their patient's colons.
So I did some poking around and i found that the Stonyfield Organic Yogurt is the best. It has 1-3 grams of fiber (depending on the flavor) in the form of inulin, which helps your body ingest the calcium. It also has 6 live cultures, which is the most of any yogurt I've seen. Combine that with the fact that it is organic, so won't be filled with hormones and (ironically) antibiotics, and a great taste (particularly the chocolate) and its a damn healthy snack.