Sandy: If you live in Deleware, hike yoursel of over to the DC metroplex, at least to "metropollitan Maryland" (ie, Maryland immediatly adjacent to DC, esp north toward Montgommery county); get a couple of GOOD maps, Such as the book map of Montgommery county, steal or borrow a yellow pages, & devote a some Saturdays to looking at the bigger music stores in the DC-Balmer area. At least get yourself over to Wheaton triangle, park in the middle (or wherever, but not over in the subway parking building; even less safe than the rest of DC) & walk around. The Wheaton triangle area is loosely defined by the intersection of 3 streets; Georgia, University & New Hampshire (if my terrible memory for names doesn't goof me up; look on the Mont. Co. map; it'll make sense). I bought a small Taylor there this past year for a fantastic price.
At any rate, don't just make this important decision w/out trying to gather more data. Also: I'd say don't have the attitiude that this'll be your last & only good guitar; chances are it won't be/can't be.. I'd advise an open mind & the notion that this'll be a chance to get a very decent acoustic, which may well open a future door to other hi class acoustic guitars.. all in good time. If your current limit of $600 is what you're stuck with, it could be a dificult choice, but it can be mannaged.
Good luck, 'n Cheers, BK