I always wear earplugs. I used to use disposable ones but got custom ones a few years ago and wouldn't hop on a bike without them.
I keep two microfiber cloths in my tank bag.. one is dry, the other damp in a zip-lock bag.
Since I wear a modular helmet I can lock my throttle and wipe my shield while riding if I wish.
I use a Go-Cruise Throttle lock. Mine holds perfectly and could lock all day as I use some aircraft safety wire to snug it a bit. Releases easily but holds perfectly.
I use a throttle lock. I DON"T use one that holds with Velcro.. they are nearly impossible to adjust while riding and I do find I like to adjust them depending on the speeds I am riding.
I love Rok-Straps. I carry a pair of large and a pair of small ones. I also carry a bungee net. Some things just work better with a net. I carry a very small, folded up waterproof bag in my topcase., I forget the liter size but I think over 30 and might be over 40. Very handy if I need to pick something up I hadn't counted on.
I take three thin moisture-wicking underwear from Mark's Work Wearhouse and three Tilley Travel Dress socks (The socks are my everyday socks for work under my suit nade tire and riding from below freezing to over 126°F /52°C.)
I have Aerostich rain Overgloves in one of my pockets. I can put them on while riding if it starts to rain and I feel my gloves might need to be kept dry. (Some of my gloves are waterproof, some aren't.)
Hydration is very important to me. I have one of those larger Gatorade bottles that I clean and refill with water.. it has the nipple kind of top so that I can drink it while riding and I don't need to fiddle with bladders, etc. Just flip up the front of my helmet and drink. I carry NUNN Hydrating tablets (available at Sail and MEC) to turn the water into a decent hydrating solution without the sugar Gatorade has (but would buy Gatorade if I ran out.)
I carry a small air pump that can connect my battery (or anyone else's) and a worm-type puncture repair kit. I have fixed about 6 flats on my two V-Stroms and one of a fellow riders. (Last puncture a month or so ago.)
I have a little USB charger (less than one inch square) that plugs into my heated gear connector. I don't normally use it since my cell lasts all day without charging but just in case.
After seeing an "Antigravity Micro-Start" that is smaller than the oversized iPhone start a V-Strom recently I bought one of those. It is very small and sits nicely in my topcase. It can jump start a car as well as charge phones, tablets, etc and has emergency lighting built in plus a number of popular connectors including the Apple ones.
I use a motorcycle-specific GPS unit. (Zumo 660.) Yes I can use a phone or my iPad to navigate but really nothing works as well as a GPS and I never have to worry about rain, heat, cold etc. I keep chain lube in my tank bag so I can lube my chain when I fill up and after every ride in the rain. (My chains typically last over 70,000 km.)
I wear an oversuit (Aerostitch Roadcrafter two-piece.) I wear this summer or winter and have worn it from below -10°c to into the 50's (in Death Valley.) It is Goretex and pretty waterproof. I wear different amount of clothes underneath depending on the temperature range.. I will often have pants that convert to shorts so that I can just unzip the legs as it warms up. Otherwise I wear whatever is appropriate street clothes under it. When stopping it comes off in seconds. The look of shorts and boots doesn't work well for me so I have a pair of sandals in my top case that I can put on when I stop.
..Tom