That's just about where I was a year ago - torn between a Marin Muirwoods and the Trek 7300FX. Went into my LBS which happens to be a Marin dealer but when I saw the Specialized Sirrus it was love at first ride.

Since it was the end of the season my LBS offered $100 off the list price which brought it down the price of the Trek and certainly better than buying it used. Quite honestly, unless you want something vintage or find a $25 garage special, or get a good percentage off a high-end bike, there isn't much point in buying used.

EDIT: Wanted to add that the Sirrus has 700C 28 tires which makes it more of a road bike than most hybrids although it still has flat bars like a mountain bike. Weight is about 22 lbs without accessories.