http://news.ycombinator.com - (duh), post with Show HN, easy submission, will get listed on
http://showinghn.com/ and
http://hnshowcase.com as well.
http://betali.st - quite well known, moderated, gets a decent amount of traffic if you get featured, not too many form fields to fill out.
http://www.kickoffboost.com - moderated, and relatively new, easy submission
http://www.reddit.com/r/sideproject - moderated, easy submission
https://www.sideprojectors.com - relatively new, easy submission
http://thestartuppitch.com - moderated, has quite a few more form fields to fill out than others
http://www.erlibird.com/startups - paid $149, last time checked out
http://forrst.com - Easy submission, used to be a great community for feedback - not sure now
http://www.bootstrappist.com - a mailing list of bootstrapped projects - has quite a few subscribers I think.
http://angel.co - Angelist, of course - new startups gets tweeted via various accounts
http://crunchbase.com - Crunchbase - similar to Angelist
http://betali.st - quite well known, moderated, gets a decent amount of traffic if you get featured, not too many form fields to fill out.
http://www.kickoffboost.com - moderated, and relatively new, easy submission
http://www.reddit.com/r/sideproject - moderated, easy submission
https://www.sideprojectors.com - relatively new, easy submission
http://thestartuppitch.com - moderated, has quite a few more form fields to fill out than others
http://www.erlibird.com/startups - paid $149, last time checked out
http://forrst.com - Easy submission, used to be a great community for feedback - not sure now
http://www.bootstrappist.com - a mailing list of bootstrapped projects - has quite a few subscribers I think.
http://angel.co - Angelist, of course - new startups gets tweeted via various accounts
http://crunchbase.com - Crunchbase - similar to Angelist