Generic Top-Level Domains or gTLDs are the extension at the end of a domain name (i.e. .com, .net, .org). Google has gone on record saying gTLDs (i.e. .com, .net, .news, .attorney, etc) aren't considered as ranking factors. In fact, Google representatives say they completely ignore TLDs when it comes to rankings. That would suggest that all gTLDs are equal. Now, this may be true with Google's algorithm, however consumers still consider .com's king, relevant and trustworthy over the others. When in doubt, register a .com domain name!
If you're wondering if your domain name should be keyword friendly, that's a different story!