These are even better, and are what I use professionally:
http://www.amazon.com/dp/B000CRY52A/?tag=atomicindus08-20
If you really want to cut heavy wire or other items (brass toilet bolts), the Journeyman linemans are sweet:
http://www.amazon.com/dp/B0000BYDNE/?tag=atomicindus08-20
The Kleins cut like butter. They have harder edges than most other pliers I have used. When I started doing electrical work professionally with my electrician buddy, it was what he used. I have Cman Pros which are very nice and Fat max lineman pliers as well, but Klein is better. Now I work for the family business and repair animal dryers, vacuums, clippers, etc. and I still use Klein. The screwdrivers are also the best I have used. They are not cheap, but most are USA made and they hold up to full time abuse.