I m big believer in .com only simply because that's how the web has always been. With more TLD (top level domains) sprawling everywhere, it only makes .com more attractive. To me, .com is like a household name...that's what people are familiar with. Unfortunately, it's Very hard to get any TLD names without paying more. I guess if you value your site alot, and wants to build a brand with it, then go with .com.
Also, imagine if you have site at www.housebutterfly.name, make sure housebutterfly.com is not taken by someone else. You'll be losing traffic to those who remembers your site as a .com.
For google, it doesnt really matter if it's a .com, .net, .tv...if you can get alot of sites linking to you, google will pick you up. For you to get many inbound links, make sure you get a memorable domain name!
Hope it helps! 