Follow-up to previous post: although I have been dealing with logic circuits since the mid-70s, I admit I am not up on the most current logic circuit family. So I decided to do some research and I came up with this:

http://en.wikipedia.org/wiki/7400_seriesScroll down to the lower two thirds of the page and you will find a chart giving various parameters of each logic circuit family up to about 2004. These parameters include logic family, circuit speed, voltage requirements and current draw. Interesting enough that the fastest chip that was listed here was the 74 "G" series which is a TTL circuit running at 1.125 GHz.

I just thought this might help someone when choosing logic circuits for their Arduino project.

Joe.