Finding the right issue tracker

I'm receiving more and more feedback via e-mail from players (both bugs and feature requests) and I've come to realize that I need to find a tool that can help me keep track of things. During the last couple of days I've tested a multitude of different bug and issue tracking systems and it's damn hard to find something that gets the job done without too much hassle. These are my requirements:

• It must be a web based tool
• It must be a hosted tool. I do not wish to install the tool on a web server of my own.
• It shouldn't have a ton of settings and configuration options. It should be sleek and ready to go in minutes.
• It should offer a free account (although I would possibly be willing to pay a small amount per month)
• It should provide anonymous users with read only access to bugs
• It is a bonus if anonymous users can add new bugs
• It is a bonus if the tool allows login using Open ID, Facebook or Google

The ones that I've tried that are still on my shortlist are LighthouseApp, FogBugz, YouTrack, Trakr and possibly also PivotalTracker. Does anyone else have a suggestion for an issue tracker?