Bicycle panniers are a great alternative to backpacks. This is also consistent with the concept of adding weight to the bicycle and not the rider. Panniers are similar to saddlebags on a motorcycle but much lighter and more versatile. They are usually made from nylon and most are waterproof or at least water-repellent. Often they are sold in pairs to balance the weight on the bike but one pannier can work if not overloaded.
They can be mounted over the front or rear rack using hooks, straps, or some form of locking system.(rear mounts are much more common). With easy removal, and carrying straps, they can be super convenient for touring, commuting, or just shopping.
Commuter pannier with laptop pouch
If you are considering panniers I recommend rear over front panniers since front panniers can have an adverse effect on steering and handling. Of course, if you are doing some serious cross country riding, and need four panniers, you will just need to exercise more caution.
Do not overload your panniers as you are likely to pick up stuff along the way (like food) that you will need some room to carry.
A garment bag pannier can keep your clothes wrinkle free. This is especially handy if you commute to work and need to wear a jacket and tie on the job. Some also have compartments for a laptop.
Garment bag pannier
f you are more of a backpack kind of guy/gal or if you are going to hike after your ride you can find a pannier to suit you as well. Or you can just let it serve double duty as a backpack or pannier.
Touring panniers are high capacity and are suitable for long tours where
a lot more space is required to hold several days supplies.
Touring panniers are usually mounted over the rear wheels though they can be used in front as well with the appropriate mounting hardware.
Another great option is a shopping bag pannier for those quick trips to the convenience or grocery store
Shopping bag pannier