Add this to your scripts/startup folder and you will always have a display of triangle count for one or more selected objects in your active viewport.
It displays "nothing selected" when nothing is selected because I deployed this script to all artists at my company and I wanted them to get accustomed to looking in that area of the viewport for this information. If you prefer it to go away when nothing is selected, just replace the line
else return "Nothing selected"
else return ""
"QuoteWare" license (idea stolen from Martin Breidt):
If you use one of my scripts in a production environment with a group of more than two people, then you are obliged to tell me about it and allow me to list that project title and your company name as a reference on my website. This tool will remain free and opensource, so this really is a very small thing to ask in exchange for using them. I hope you all agree.
Thanks, and looking forward to hearing from your project!