.net is for company,.com is for personal use.but .com is much worth then .net,people would like to spend huge $$$ in buying sex.com,but no one would like to spend the same $$$ for sex.net.
I was under the impression .com stood for .company. I agree with everyone else, .com all the way. I've never purchased a .net, even if that great name was unavailable for .com and the .net name open. There's a free ticket to the competition. HOWEVER, it doesn't hurt to buy your name in every TLD...
.com was originally for commerce, .net was originally for networks (like ISPs), and .org was originally for licensed and registered organizations. Note I said originally.
A .com should definately be you're 1st choice. If the .com is taken, then the 2nd choice would be a .net. The .com will always be worth more than a .net of the same name. As far as Google, it doesn't matter which extention you have, Google treats them equally. Hope that helps.