I've had several Lenscoats (they're neoprene I think, not silicone) and found them to be very useful for keeping white lenses clean, including on African safari. I've never noticed any scratching from dust/dirt being caught underneath but I think an occasional inspection and removal would prevent any lasting damage.
I'm surprised to see so many suggesting a battery grip. I've always thought they looked too bulky, plus most of my work is in landscape mode, but I'll have to try one sometime!
I'll check out the other products that have been suggested.
A grip on a 1 series is rock solid, but on a 7D, I'd pass. You do not hold a camera with heavy lens by the body / grip combination, you put a hand under the lens to support it.
I've had a lot of grips, and took them all off.
Unless you have a specific need such as portrait orientation or extended battery life where you can't easily change a battery, I'd pass.
You know, I think Mt Spokane has a point. I'm sitting here looking at no less than 4 grips in a pile waiting to be sold. I simply never use them anymore. No offense but I almost feel like they are newbie-bait. I purchased and used them for a while when I first got back into photography and purchased them with each new body. The last two never left the box.
So I would definitely wait on the grip and perhaps also evaluate how you hold your cameras with heavy lenses.
Also, skip the silicone skins and such. They just get in the way and if you leave them on, dirt/sand/dust, etc gets in between the camera and the skin and will wear/scratch the body worse than if you had nothing on it at all. Total waste of money!
LCD protection? Sure, why not? It's not expensive and doesn't hurt functionality, etc.
Black Rapid Strap? Before you buy one, head over to this thread first... http://www.canonrumors.com/forum/index.php?topic=19962.0