Mission Workshop Messenger Bag
Mission's messenger bags are hewn from rubber-backed nylon fabric and use sealed zippers and a roll-top closure to keep water from seeping in and soaking your stuff. An oversized aluminum buckle provides easy one-handed strap adjustment, and there are two quick-access outboard cargo pockets. The bags are offered in three sizes starting at $149, so you can carry anything from your laptop to a load of laundry.
Ducati Corse Pack
For the Ducatista who has everything and needs a way to carry it, Ducati and Puma have teamed up to offer the MotoGP Corse pack. At $85 it's a deal as far as Ducati swag goes, and will fit in quite nicely in the hospitality tent at the next USGP. It's got a padded laptop compartment and is made from a heavy, glossy-red vinyl that only diehard tifosi can appreciate.
Timbuk2 Swig Backpack
Timbuk2's line of highly functional backpacks and messenger bags was originally designed for bicyclists, but works just as well for motorcyclists. The Swig bag has all the standard organizational accoutrements, plus cool touches like an on-strap bottle opener, accessory loops for affixing gadgets and gizmos, and a secret zippered pocket for your spare key or emergency gas money. It comes in a bunch of creative color combinations for $90, or you can design your own using a slew of custom fabrics and colors starting at $100.
Baby got back...pack.
Kriega R25 Rucksack
Kriega's R15 is the BMW R1200GS of rucksacks, with the versatility to do anything and go anywhere. Designed for stability and comfort, the $109 pack uses Kriega's Quadloc harness system and grip fabric at body-contact points to keep it in place. Four synch straps compress your cargo while integrated clips keep the strap ends from slapping you silly. Compartmentalization is kept to a minimum in favor of large-item swallowing capacity, but there are still sleeves for your laptop and hydration system.
Aerostich Courier Bag
A Tim Carrithers favorite! This motorcycle-specific, single-strap courier bag offers everything you need and nothing you don't at an affordable $87. The triangular profile of the main compartment helps settle your belongings so everything stays in position while you're riding, and it'll hold a small briefcase with room to spare. Aerostich offers its messenger bags in several size and color variations, including the viscerally upsetting and always popular hi-viz yellow shown here.