For many thousands of miles, I ran my bike with a set of soft throw-over style saddlebags. These bags were made by Willie & Max, and served me very well. I could cram a LOT of stuff in those bags, and would often load them FULL on long trips.
These throw-over type bags are fairly inexpensive, and come in all sorts of shapes and sizes. They usually have a strap that crosses the fender under the seat, and are very easy to install and remove.
Click HERE to see more of my previous Willie and Max bags...