For TS you can get tea, coffee, hot cocoa and juice. If milkshakes and smoothies are on the menu they usually count. I say usually because there always seems to be an exception to every Disney rule somewhere along the line.
With CS you also have the basic choices as above and will probably find that the counter service locations which serve shakes and smoothies, don't have a proper menu, making it impossible to redeem a CS credit for an entree, dessert and a beverage like a shake or smoothie.
Some places however have cappuccino, iced or latte on the menu and those will allow it - again, subject to change or variation at any point. Main Street Bakery make a pretty decent cappuccino and I have had my share of CS meals from there and had no problem getting my special coffee as my beverage.
If you go somewhere like the resort food courts or Sunshine where they have a selection of beverages in the self serve fridges you will find more variety there too.