Having guests and entertaining are broad terms; they really do not say to be able to give to advice on. A more specific definition, especially of the guests needs to be given for any advice, because it is really the guests that dictate the wine selection and etiquette of the evening. Hosting a dinner party for parents or in-laws for example is almost bound to be a little more formal than a simple cheese and wine thing with some friends. The difference between these two events is like night and day when the wine selection is concerned.
A simple gathering of friends can involve an adventurous new wine; a risk may not be as good of an idea with guests to impress. This is not to say that a conservative, tried and true wine is the only way to serve parents, but maybe have one on hand just in case. Friends on the other hand are likely to enjoy anything from the two bottle wine bags 
because they are having a good time. But of course it is a matter of knowing the guests and some idea of what they would want in either a fun evening or a formal dinner.