The variety of pipes -- shapes, materials, nations of origin, prices, and smoking characteristics -- along with the vast variety of tobaccos and relative thrift compared to cigars, and the ability to have a thorough enjoyment even on a bowl or two a day, with days off. The pipe community is a huge plus -- shops, shows, and Forums at the forefront of that, plus some totally unique people who do it their way. I like occasionally mixing tobaccos and blends, plus appreciating the artistry of the various lavishly talented blenders.