yes .com first choice for a commercial site.
If you can't get the name you really want try .biz
but be prepare to lose visitors to 'yourdesiredname'.com
I have no favorite cause I like them all, .net sounds techy. but it all depends on the site im making. I use whatever fits with it. Like my personal site is .com and my JTHM fansite is org because its an organization of fans.
Obviously if you are looking for a site, i believe most people will give .com a try 1st
yeah .com is the more know and if you want people to remeber your site easily its best to have a .com however if you personal page is somehow related to a not for profit organization like a charity then .org is the way to go since thats what its supposedly there for.