I generally carry an assortment of crap on a daily basis (bags stay on).
Under seat, forward pan holds Slime Pump, OEM tools
Under seat, rear pan, Stop n Go Tire Plugs
Bags:
Canyon Dancer strap
Aerostich "Vulcan" glove rain covers
Ultralight bike cover (packs to size of small book)
Tool bag containing a variety of sockets/wrenches/screwdrivers (fitting the most common fasteners and things of that nature), multi-tool, knife, spare bulbs, tire strings/glue, fuses, elec tape, and zip ties.
Alarmed cable lock
Rag or two
Plexus/microfiber cloth
Spare gloves
Rok Straps
Dark/light shield (Usually leave the dark at home on multi-day runs)
A few bungies (Rok straps see way more duty)
Plastic shopping bag, large
Jumper cable extension that plugs into Batt Tender cord
Tank Bag:
Digital Tire Gauge, plus analog backup
Pen
NC Map (or other states...I cut up the plastic pages from my old truck driver's atlas to use)
Bottle, Vitamin I
LED Maglite (small)
Swiss Army Knife
Baggie full of ear plugs
TB rain cover
Baggie full of quarters