Typography is too important and broad a topic to break down to a simple favorites list. Getting really involved with type and learning as much about it and its use as you can will help you to separate yourself from your competition and improve your business.
Start by exploring what a leader like Adobe has on their website
HERE.
Next start looking (if you haven't already) at type in use. What do you like about this sample? What do you not like about that one?
At the core of type use, understand that type falls into two primary categories of use: Headline and paragraph. Some styles are very easy to look at when there is a lot of it and some should be use sparingly.
For paragraph styles I prefer to use a large family so I have lots of options as to weight, italics, small caps, etc. I also like to use styles that I know my nearby competitors haven't adopted. For me those are Adobe's Utopia font family for a serif style and the Frutiger font family for a sans serif style. I also use a lot of Futura and Serpentine Sans which crossover nicely for either paragraph or headline use. In serif I draw on the Garamond and Palatino families when I need a change from Utopia.
For headline text I use nothing but Old English, all caps at 50% of normal width and arched. (just kidding)
Seriously though, I love SignFonts Snapper Script and have had to force myself not to use it for a while because I was using it too much. House Industries Signpainter Script is definitely worth adding to your library.
But first determine what you want to do with the type and what kind of feeling any given headline font will communicate. Avoid gimmicks, condensing, expanding and, in general, monkeying around with well designed type. Let the good design that has already been put forth work for you.
Overused and common fonts to be avoided:
Brush Script
Comic Sans
Times Family
Arial Family
Brody Script
Dom Casual
Avant Garde