Chinook is a high alpha hop and lends well as a bittering hop. It's a bit earthy, piney and grapefruity. Citra is an excellent aroma and flavor hop with a lot of tropical fruit overtones, like mango, lime, melon-like flavors. Willamette is a Fuggle-like hop and is used mainly as an aroma hop. It has a spicey, woody aroma.
IMHO, you have great hops for doing a nice strong IPA.