Bark Busters are very strong and you can get accessories such as the "storm" plastics and even extra bar end weights. They also easily let you use the very cheap and effective "caterpillar O ring" throttle lock. Otherwise the Highway Dirt Bikes ... HDB guards look pretty good.
I have just completed a 6,500 km ride in Australia and was very pleased I had a Brittannia Composites Mirage 2, which is an adjustable Rallye screen a bit like the more expensive Touratech Desierto. Very pleased with it ... drop the screen down for offroad, raise it for rain, cold and highways. The aerodynamics are obviously good as it really helps having the screen up when passing trucks and road trains coming the other way compared to having it down. An unexpected benifit was better fuel consumption. I travelled with up to four other F800GS's and I always used a bit less fuel if we travelled at the same speed, I guess its just the aerodynamics again. The new cockpit works well too with the relocated instruments and a really good place for a GPS. I highly recommend these, but the adjustable Wunderleich looks good too if you want something more conventional.
Handguards - I'd recommend Bark Busters. Mine have been tested and stood up well. Also if you completely scrape them then it's easy to get replacement plastics and just sand/file the bars. I would say in something serious the handlebars would bend before the BB's
Screens - Touring or off-roading? One thing i would recommend is trying before you buy. If there's any GSer's near you then ask what they've got in their garage / shed / loft before you start shelling out. I've got 650 stock, 800 stock, Wunderlich Vario and am just trying the MadStad. If you're gonna make it as far East as Reading drop me a PM.
On an aside - There are various issues with handguards touching screens. My BB's don't touch any of the above or the powerbronze/meta mule offering (not on the above list. RIP.)
Best of luck,
S
PS have a look at recent Top 5 Mods post if you're suffering a bout of farkling fever