NOW What, I'm a failure, what can I do, what can I do

. Anyhow now that I'm done with that, I wonder if I get that Garmin 500 edge, can I download any software to give me a more accurate reading for Watts or power used. I know a lot of guys on the road forum use the same link that I've been using, but that's not saying much either. I can't get a power meter right now and I really don't think I need it, for the kind of riding I do. I was basically using that web site to find out how many calories I used for the ride. If the watts are off that would mean the Calorie readout would be wrong as well. I guess all I can do is check how far I've gone and the average speed. The thing that comes to mind now is, what did riders do before the power meter came out?
I think the HRM comes in handy and now that I know my maximum HR is, which is 169, I have a my different Zones figured out. So that does help, but I would still like to get something to figure watts out, beside a meter. Anyhow thanks for setting me straight on that web site. You wouldn't happen to know a better one would you Rich. Thanks for the reply.