I got my second kettle packaged with a turkey fryer at the HD. I definitely recommend a turkey fryer if you don't have one. 6-7 gallons of water don't boil for a while on most stoves.
Anyways, I use the Denny method. It works great for me. I just send my second running right out of the mash tun into the first that is already heating on the burner too.
The two chillers, one in the ice bath, works great too. Use some rock salt in the ice and you will get colder water returned. You can find salt that's for ice cream machines. Its meant for that sort of thing. I tried salt today for the first time and got better results. Also, I got the cheapest smallest copper chillers out there and they take twice as long to chill wort than what trapae mentioned using the same ice method. Just a thought.