I only track plants I have, it would be depressing to track ones I've killed, and I keep a running Wish List as a Word document that I print and take with me to nurseries.
Categories I use are type of plant (tree, shrub, perennial, etc), use (aromatic, medicinal, edible, etc) and I also have a native and invasive category. I use invasive to indicate non-native invasives for my area, not whether the plant is otherwise invasive (a la most ground covers). Each plant might be categorized in 2-3 ways and I can run specific lists (e.g., native trees or aromatic perennials) as needed.
A more personal category is "Start for Laur" which are all the plants I have that my sister would like a start of. Makes it easy for me to know what to chunk off in the spring when things start emerging. She and I are in different zones but can often share bounty.
