For beer - a 6gal carboy (glass or better bottle). Being able to see what's happening is helpful to me. And, it's entertaining!
For wine - a bucket for the primary. Not as much to worry about with wine. And, not as exciting to watch.
Atomic Dog Brewery
On Deck: Centennial IPA, Dry Irish Stout
P: Cascade Pale Ale
T: Carbed Crystal Light, Root Beer, Vanilla Cream Soda, Tripel IPA, Apfelwein
e^(pi*i) + 1 = 0