Include a portable version that enables you to use it on all of your computers without having to install it on each one. This would also cut down on registry additions and other impacts.

Once again it has to be said: 'portability means piracy'. If a program isn't installed on an individual computer then it can be installed on any and all computers. People here know software will be stolen if it's not 'written in' to a computer and its registry.
If you expect payment for your daily work then it's fair to expect software publishers to resist piracy and to get paid for their work.