Great question ikeathesofa! I was reading everyone's reply and there are some good well thought out opinions here. However, on this topic, I agree with BBYY. If I had the money and space, I would prefer to grow all my plants in five gallon containers. The advantages for me would be less watering, less feeding, and less shock to the plant.
I don't agree with the poster who said it promotes foliage growth. Now I could be wrong, but it's my understanding that plant growth is mainly due two hormones in the plants, gibberellins and cytokinis, which are stimulated by the light cycle (e.g. root growth during the day, foliage at night). Someone else mentioned something about a higher risk of algae if you grow in a large container. I think this is only true in a medium that doesn't drain well or if the gardener habitually over waters their plants. And that's more of a human error then a problem with a large growing area.
The reason why I wouldn't go with seven, ten, or even a twenty gallon container is because frankly, the plants wouldn't live long enough to fill up the space. It would just be a waste of resources. Even five gallon containers can be considered a little wasteful. That's why this season I'm using three gallon containers. I feel this is a good balance of giving the plants ample space to grow, while reducing the amount of nutrients & water I need to buy and use.
I choose to grow indoors in dixie cups because I've learned that genetics overwhelmingly dictate the plant's yield, potency, and vigor. I like to germinate as many seeds as I can fit under a 125 watt CFL light. I'm murderous when it comes to picking my mothers. I may germinate 20-30 seeds at once, but I'll only allow a handful to grow for more then a week. I'll continue to evaluate them until I've decided on my keepers. And it's of those plants I make my clones from.
I'm a big advocate of buying cheap nutrients, keeping it simple with lights and containers, and go broke buying seeds.