helmet (with brim)

 rear rack

 panniers

 handlebar bag (optional)

 water bottle

 lock

 red tail light (blinker ok)

 white head light

 tool kit

 safety vest

 pump

 bungy cord to attach stuff to rear rack

 cycling gloves

 sunglasses

 sunscreen

 pocket knife

 toilet articles

 camera and film

 money

 personal medication

 cycling shorts

 cycling tights

 2 T-shirts

 cycling shoes

 socks and underwear

 sneakers

 casual clothing for evening

 wind shell (breathable)

 rain suit or poncho (MEC Bernoulli Jacket)

 bathing suit

 pajamas

 bandannas

 plastic bag

 15 cm adjustable wrench

 tire levers

 tire patches

 chain lubricant

 straight blade and cross-point screwdrivers

 metric hex wrenches

 extra nuts and bolts

 sewing kit

 Few panniers are completely water proof. If the weather is threatening, wrap the contents of your panniers or handlebar bag in plastic.

 Roll clothes and store in large zip lock bags (sit on bag to squeeze out air then seal)

 Keep valuables in an easily removed bag that can be taken with you when you leave the bike (e.g. handlebar bag)

 Keep list of your valuables (serial numbers) with your traveler's cheque numbers (if you use them) separate from your wallet

 Keep rain gear and tools easily accessible

 Generally put heavy items low and towards middle of bike

 Leave space in your panniers for temporary loads like groceries. The extra space makes packing go much faster.

 Good master list at http://www.stanford.edu/~jcolwell/bikelist.pdf