Many people are scared of volume thinking it will make them appear fat or broad. What most people don't know that only a few of us do know is that volume in select areas will actually minimize problem areas. Puffy sleeves can minimize the attention someone will pay to your less than attractive areas. I use the camouflage of puffy sleeves to hide my tummy. It can work to hide a larger bootie as well. For a normal, average person (who does know how attractive these sleeves can be) I suggest going for a slight to medium pouf. If you are super daring then go for an exaggerated Dolce and Gabbana sleeve.
To me adding volume is an easy way to incorporate a touch of femininity in the form of jackets, blouses, and dresses. There are some pretty interesting puffy sleeves available now more than last year so get out there and jump on the puffy sleeve before the volume shifts to another area like say a reinvention of the bustle.
Puffy sleeves don't have to be used for more formal events. Just a note this is completely different from the strong and severe volume of shoulder pads. Last year I patterned and made a jacket that I have been able to wear to work, on a date, and to church. I am now tempted to wear a bigger pouf though. I also have really taken a liking to the Burberry coat and now several line copies.