Small, Medium, Large
Bronze, Silver, Gold
Three ways to say yes and one way to say no!
The Law of Three choices: give three choices (in products, what team could do next, etc.) and it is easier for them to make a choice. Fewer options, and some feel forced or/and that there are not sufficient options. More, and people feel overwhelmed; they are less likely to choose, and if they do, they are less satisfied with their choice. (Ideas from The Paradox of Choice)
Every time you provide an option, you're asking the user to make a decision. That means they will have to think about something and decide about it. It's not necessarily a bad thing, but, in general, you should always try to minimize the number of decisions that people have to make.
CHECK OUT JOEL SPOLSKY "CHOICES"