I second Bearpaw's praise of Mt. Rogers/Grayson Highlands; I've been there twice, and it's tied with Isle Royale as my favorite place ever to go.

I don't know that you need any special gear in that area; I just take my standard three-season gear and never had a problem. Depending on your exact time frame, check out the ten-day forecast; it is cooler up in the hills than in town, so you might want to take along a fleece jacket even though it's August. (What the heck - it would make a great pillow if nothing else.) I was there in late April and mid September, and was glad I brought a down sweater both times, for evening. I also recall one misty morning on each trip where I wore a long-sleeve synthetic top instead of short-sleeved tee shirt.