I think people associate .org with charities and non-profits (PBS, NPR) but not necessarily open-source software. I’d go with both.
just use the .org as official site and redirect the .com to .org simple
Most people assume that a domain name ends with only a “.com” and they may not be aware that even .net or let alone .org exists 
Each TLD has a specific advantage in it’s area.
.com -> commercial sites.
.net -> networking
.org -> non commercial organizations, opensource projects
.com domains make more money, if you ever decided to sell it.
Use the .com if you can. People will use that first when looking for your site. It is better for off line advertising also easier to remember.
I think this thread lost its meaning a long time ago. Basically the OP wanted to know which was better for SEO.
You have a chance to go .com then go for it. If not then treat the rest as the same value. For SEO value I think they are all the same but inherent values for .com domains seem to be greater.
no difference for seo … originally i understand .org was established primarily for non-profit organizations and .com for profit organizations … otherwise, no difference for seo
I agree. .com has the best name recall for most people. And I asked a number of people and majority of them think a website projects a wider scope when using .com instead of .org.
I say register both but use .com .
I think .com domains tend to fetch more money, if you ever decided to sell it.
So very true.
I always use .com no matter what my sites are about or for. I have romanian websites with 50% romanian content that are .com :). I rank very well with it for romanian keywords so, just use .com
I think the main reason why I use .com is because people tend to just use .com .for example a friend once told me, a few years ago, ‘visit youtube’, and it wasn’t necessary to tell me that it was .com, even if I never heard until then of youtube. It’s just how internet developred.
I go for .com and .net before looking at .org personally.
For SEO, I second Stymiee, for all other practical purposes, buy .com
Pick 'em both up if both apply, but users who type the address in by hand are likely to forget the extension if you don’t use .com.
I beleive that a .org is going to make you more money on donations. you know people associate .org with non profits… meaning they will feel more comfy payin on a .org than a .com
the difference in .com’s is only popularity nothing else i beleive orgs thou are better for making money
There is no real SEO benefit, so use .org – it is more suitable for open-source projects (linux.org, mozilla.org, drupal.org, wordpress.org, but ubuntu.com. weird.)