This is so hard because I am so pro Sto. Dgo.:-( But if you love beaches, then there is no question that Punta Cana is it! There are no true beaches in the capital, but SD is THE place for nightlife, excitement and Dominican culture and history. IMHO the best casinos are in SD as well. Can you tell I am secretly reeeeally selling you SD here? (LOL)
In Punta Cana, I suggest that you stay at the Bavaro city, errr, I mean complex. The Bavaro complex has a nice casino. I think staying here would definetely fit the bill for what you may be looking for. If you go early in January, the Bavaro will most likely still be decked out with their Christmas decorations. The complex is BEAUTIFUL during the holiday season. HTH!
Regards,
Natasha