My current bag (19 discs):
3 Putters - all Star Darts at varying weights
5 Mids - Star Stingray (understable turnover disc), Z Buzzz (slightly understable to stable upshot disc), 2x 2010 Ace Race discs (overstable short-range drivers and upshot discs), Star San Marino Roc (for when I have to take the Ace Race discs out of the bag for sanctioned events)
3 Fairway Drivers - Champion Leopard (turnover driver), Champion TeeBird (beat in and super straight), Star TeeBird (brand new, with a bit of fade)
3 Utility Drivers - Champion Roadrunner (roller and anhyzer disc), DX Dragon (water disc), Champion Firebird (overstable driver, overhand disc)
5 Distance Drivers - ESP Nuke (max-distance high-turnover driver), Z Nuke (very new, stable turnover driver), Champion Destroyer (headwind driver), 2x Champion Wraiths (slightly understable drivers)