Zinfandel is a wonderful variety that can be strongly influenced by where it is grown. Below is a quick reference:
Amador County: Big, full bodied, extra ripe and jammy
Santa Clara Valley: Known for conplexity and depth
Sonoma County (Dry Creek Valley): Juicy, bright fruit, balanced acidity, blackberry, anise and pepper
San Luis Obispo (Paso Robles): Soft and round
Napa Valley: Plummy, intense, red berry, cedar, vanilla - Claret style
Russian River Valley: Often Old Vines, spicy and somewhat lower in alcohol than other Zinfandels
Mendocino County: High quality, lesser known, not as heavily marketed
Lodi: Juicy and approachable, some of the oldest vines