Sensible suggestions that will make your trip more enjoyable.

Do Not Overpack
Travel gurus unanimously list overpacking as one of the most common travel mistakes. On a long distance bicycle trip, the extra weight of unnecessary items can make the difference between a fun trip or a disastrous one.

Factors Affecting Gear Selection
Inevitably, the gear you will need for your trip will depend on the distance you will travel, access to food along the journey, weather conditions, where you'll sleep, how your bike handles the gear load and whether the trip is supported.

Specific Gear Suggestions
Assuming that you are embarking on a multi-day bike trip, I have broken the gear you will need into 2 categories:

USE COMMON SENSE
These packing lists are NOT definitive but they've worked for me. Base the gear YOU will take on YOUR comfort level and the factors I mentioned above concerning gear selection.

Do A Dry Run
Several days BEFORE YOU GO on the trip, do a dry run. Pack everything on your bike to see that the load is stable, THEN ride your loaded bicycle at least a few miles to make sure you are comfortable with the load. If something doesn't seem right, redistribute the weight or eliminate items until you ARE comfortable.

Trips w/Beds:
What To Take When Staying In A Hotel, Motel, Inn or B&B
On such trips, I've gotten by with about 35 pounds of gear loaded into a suitcase or rear panniers, a handlebar pack and a fanny pack. Here's the complete inventory:

__ Bicycle Helmet
__ Sunglasses
__ Cycling gloves
__ Pants clips or velcro straps (keep your pant legs from getting dirty)
__ Waist/fanny pack
__ Two pairs of hiking shorts (Velcro-closed pockets a plus)
__ One pair of long pants
__ Two pairs of bicycling undershorts
__ Two pairs conventional undershorts
__ Three tee shirts
__ Three pairs of socks
__ One pair of ordinary athletic shoes
__ One sweatshirt
__ One light nylon anorak, with hood (for rain, wind & warmth)
__ Nylon pants (for rain, wind & warmth)
__ Pre-moistened towelettes
__ Small, basic first-aid kit
__ Toothbrush & toothpaste
__ Shampoo
__ Disposable razor
__ Sunscreen
__ Camera, extra film
__ Pen and paper
__ Cellphone
__ PDA
__ Maps, copies of pages from guide books
__ Headlight, taillight & extra batteries
__ Water bladder (Alternate: 2 bike water bottles)
__ Pannier rain covers and plenty of zip lock plastic bags (to keep your gear in)
__ Bike U-lock and six-foot cable
__ A few bungee cords

FOR THOSE ON AN INDEPENDENT TRIP, ADD A...
__ Bike repair gear (air pump, cables, spokes, tube, patch kit, chain lube & duct tape)

Camping Trips:
Camping involves greater self-sufficiency as you will be providing your own shelter, bedding and sustenance (food). To avoid repetition, add to the list below everything in the list for Trips w/Beds. Expect all the gear to weigh no less than 50 pounds. Here's the additional inventory you'll need for camping:

__ Tent
__ Ground tarp
__ Foam mattress pad
__ Sleeping bag
__ Camping utensils (fork, knife, spoon, can opener)
__ Food
__ Cooking gear

I consider the above to be the minimal gear needed to comfortably support an independent bike trip. Obviously, you will need other items (money, identification & travel documents are a few things that come to mind) so factor the specifics of your trip with your comfort level and how your bike handles the weight to determine exactly what you'll take.

Happy trails!