Thanks for the responses. Because this was my first shot at all grain, I wanted to make sure I stuck to the recipe. This is what I see (Stone IPA):
12 lbs 12.0 oz Pale Malt (2 Row) US (2.0 SRM) Grain 1
14.0 oz Caramel/Crystal Malt - 20L (20.0 SRM) Grain 2
0.6 oz Perle [7.0%] - Boil 90 min Hops 3
0.4 oz Magnum [14.0%] - Boil 90 min Hops 4
2.0 oz Centennial [10.0%] - Boil 15 min Hops 5
0.25 tsp Irish Moss (Boil 10 min) Misc 6
1 pkgs British Ale Yeast (Wyeast Labs #1098) Yeast 7
1.0 oz Centennial [10.0%] - Dry Hop 0 days Hops 8
0.5 oz Chinook [13.0%] - Dry Hop 0 days Hops 9
As you can see there is two listings of dry hopping for 0 days. I've seen this in other recipes as well. However, based on the responses, it appears generally speaking that 7 days is a good number for dry hopping.