Since you particularly enjoy birds, I'd recommend Florida -- it has wider variety than any other US state. Other places can be great during spring migration season, but Florida is awesome year round.


I'll second the suggestion for the Pacific Northwest. There's a reason why our area has a more-than-average preponderance of photographers: there's a tremendous variety and beauty of nature out here. Naturally I would suggest my own area:


http://en.wikipedia.org/wiki/Portland,_Oregon





There are a tremendous variety of photographic subjects within two hours driving distance. City, ocean, mountain, waterfalls, rainforest, true desert, starry skies, and everything in between. Some people think the clouds are a problem, but actually it makes landscapes infinitely more interesting than the boring cloudless skies of the southwest. As for the rain, well, there's a price for keeping everything green. []


Another location I would highly recommend is British Columbia. I vacation regularly in Vancouver, Victoria, and Whistler precisely because the natural beauty abounds with photographic potential.