It all depends on what you want to do, what the weather is going to be like and how long you want to go for.
Take as little as possible most things can be bought on road.

Must haves for a bike traveller:
bike:
Mountain bike for all terrain adventures, or 700C cross bike if plan to be mainly on road.
gears: 21speed and up derailleur or 5 speed and up hub gears.
suspension: Front suspension forks for added comfort and control off road. Either: Elastimer model for easy maintenance, ideally adjustable compression and rebound to reduce power loss on climbs and on road. Or: Air shocks for performance and weight if you can deal with pumping them up every couple of days. NRS rear suspension if plan to take on technical off road.
pedals: Standard pedals with clips, (clipless SPD are better but you need to carry an extra pair of shoes)
saddle: Comfort saddle with wide supportive rear; groove or cut out design to reduce pressure on private parts.
post: Suspended seat post for comfort if touring.
brakes: V brakes or mechanical disk for trails, cantilever ok for touring. (not hydraulic as is difficult to repair on the road)
frame: Cromoly is a more flexible material if you have no suspension for added comfort, aluminum if you have front suspension. Make sure it can fit a luggage rack. Full suspension bikes are usually non adaptable apart from Giant Sierra Nevada.
hubs: Strong hubs, Shimano Deore (or equivalent other brand) and up. Must have quick release.
spokes: DTswiss spokes are the strongest.
rims: Alloy, strong, standard size (not aerodynamic).
tires:
trail riding: ATB tread, 26" 1.9-2.2.
trail & tour adventure: continuous tread or slicks, 26" 1.75-1.9.
road adventure: 26" road tread 1.5-1.75/ 700C 35c
grips: comfortable ‘Kraton’ sure stick.
bars: 600mm riser bars for more comfortable riding position.
stem: Adjustable stem for on road adjustment, or fixed stem according to comfort fit.

accessories:
lights: either: front halogen strong beam, back LED flashing lights
or dynamo lights eco-friendly and for convenience of not having to carry batteries.
luggage racks: Rear: strong aluminum with wide side support for panniers.
Front: optional for better weight distribution.
mudguards: front and rear plastic lightweight fenders a must for touring.
horn or bell: a must for the city.
pump: small size but strong with Schrader and Presta valves.
water bottle cages: at least two, one with adjustability to carry large sized 1.5 litre mineral water bottle.

bags:
rear panniers: strong water resistant, large capacity, good secure connection to bike, not quick release as side connection is usually too weak meaning bags bash into side of bike when off road.
front panniers: good for touring. or
handle bar bag: strong stable connection to bar, water proof, strong.
day pack: 20 - 30 litre capacity, comfort tight fit, sweat resistant design.
tool bag: connect under saddle.
bike bag: carry bike on public transport, must be light, compact, capacity to fit your bike.
camel pack: optional, more convenient to carry bladder in day pack if need more water than can be carried on the bike.

tools:
adjustable wrench / spanner: lightweight
multi tool: Allen keys, Phillips and standard screw drivers, tire remover.
chain tool: good strong proven tool that breaks and re-connects chain.
puncture repair kit: new fast patch design or traditional, just make sure you have one.
spoke tightening tool: ideally round design for easy adjustment of spoke tension to keep rim straight repairing buckled wheels. One weight saving design is to incorporate it into the seat collar.
rear cassette removal tools: The rear cassette / cogs, need to be removed to replace broken spokes, you need a tool to fit into the cassette, each cassette has a different size, check yours. To remove the cassette you need to turn with the direction of the freewheel there for you need a piece of chain to hold secure the wheel.
lubrication: cycle oil.
pliers

spares:
inner tubes, spokes, brake and gear cables, links for the chain.

clothes:
water proofs: Gortex trousers and jacket, cycle cape, gortex booties to cover your shoes in the wet.
footwear: sandals and sports shoes
eyewear: colored lens sunglasses to reduce glare and protect eyes from dust and insects not black lens no good at night.
gloves: comfortable bike gloves with gel inplants to reduce vibrations to the arms.
shorts: preferably casual loose fit look with padded bum.(not lycra skin tight as can be offensive to some cultures and just don’t look good!)
top: quick drying material, preferably casual loose fit, football (soccer) shirts are ideal.
hat:to protect from sun and rain, secure fitting with rim. Preferably not a baseball cap as ears and neck will get sun burnt.
helmet: good to have for safety, make sure it’s comfortable.

cold weather:
thermal underwear: long johns and top.
socks: thermal design.
scarf: to wrap around head and neck, Kashmir wool is most comfortable.
balaclava: keeps face and head warm.
fleece: jacket and trousers.
gloves: thermal design.

Survival:
If you are going on an adventure to remote underdeveloped regions where you might not find a place to buy food, water, or shelter for days.
water filter: portable(light), efficient(quick), effective(kills all bacteria) many brands: PUR.Katadyn
camp stove: best to have petrol (gasoline) stove as fuel easy to find.
pots and pans: light compact.
tent: lightweight (under 2kg) and waterproof (two layer design).
bivi bag: not sure you will need a tent a bivi bag is basic protection from rain but only 300g+
knife