Great question! With all of the media hype surrounding yogurt, it is always good to go back to basics and remember what the true benefits of probiotics are in the first place. 

We have established a symbiotic relationship with the bacteria in our gut since the beginning of human existence. Over time, we have evolved to be dependent on them, and them with us. Maintaining a healthy gut, as mentioned in the post found HERE, is key to feeling your best. Probiotics are beneficial bacterial microorganisms that set up residence in the digestive tract and alter its functioning in ways that are claimed to reduce diseases such as colon cancer, ulcers, and other digestive issues. Furthermore, probiotics may help reduce the allergic response, improve immunity, and help fight off infections. Gut bacteria produce vitamin K therefore eating yogurts with live active cultures have probiotic effects, and also supply the body with calcium and vitamin D. Be sure to check the labels of dairy products before purchasing to ensure they contain active bacteria cultures and are vitamin D fortified - as not all brands are. Organisms most commonly found in yogurt that provide probiotic effects include Lactobacillus and Bifidobacteria (so look out for these). 

As for Greek versus regular yogurt, a few things to keep in mind. While I do not recommend one over another (since both contain beneficial probiotics), there are some stark differences that can effect one's decision to purchase Greek over regular (or visa versa). Greek yogurt is higher in protein (Greek-style yogurt is usually regular yogurt with thickeners, protein powder, and bitter properties added to it to make it look and feel like Greek without the work of straining). Protein helps delay the absorption of carbohydrate, enhance satiety and keep hunger cues at bay, and can help a person with higher protein needs achieve them easier. Regular yogurt may contain more sugar (and more carbohydrates), and therefore more Slices to the day (from my book, The Slice Plan). However, if you make sure your yogurt does contain probiotics (because not all of them do), it all falls to taste. If you do not like the taste or texture of Greek yogurt and do not take a probiotic supplement, it is certainly not bad to go with the regular kind. Depending on your nutritional needs (probiotics, protein, calcium, etc.) and taste, either are fine choices! 

Hope this information helps. Happy Eating!