If everyone has a different definition of the perfect panniers, why not create your own? Post your pannier projects, past or present. As this touring season warms up, I'll be creating my own panniers, and sharing my progress throughout. There are several sources of information about making your own storage system. To get the juices flowing, here are some great resources on a variety of possibilities.
Ken Kifer provides an excellent primer of design considerations for cloth bags. His site walks through several generations of flaws and improvements, and offers a shorter learning curve for any designer. Yours can be very generic, or they can be made to fit your favorite equipment load.
Steven Pav focuses on the more technical aspects of design and the process of sewing. Presented as a scholarly paper, this offering goes into much detail about the actual constuction once the design is completed.
If sewing is not your thing, there are many other options.
Paul Woloshanky used Army surplus packs to create rough and ready storage. These packs can be very quickly prepared for bike touring by adding a back stiffener and some hooks. Most Army surplus bags are made of cotton (canvas) but are said to be quite water resistant. The downside is that they are heavy when dry and very heavy when wet.
Our own
Sebastain Toney made a storage system similar to CobbWorks' Polyethylene bucket design. Any rectangular plastic bucket can become a waterproof pannier just by adding some hooks to attach it to your bike. These buckets protect their contents from squishing, but lack frills. They are multifunctioned, becoming a camp chair or stepstool at need. These are the cheapest and easiest panniers to make, as suitable buckets can be freely found anywhere.