An Alternative for MS Project

Earlier today I put out a question twitter, what is a good open source alternative to MS Project? I am asking because I am about to create another WBS for a project and I think its more professional to have a Gantt chart and a clear delination of where milestones are, than if shown in a spreadsheet.

Additionally, I am a supporter and advocate of many open source tools vs. their costly competitors in the Enterprise. I mean there is nothing wrong with the big guys. Some of their products are amazing and there is no replacement. For instance, I usually use Google Docs or Open Office for writing proposals. But when it gets proprietary and complex, nothing can replace MS Word.

So with that, I share with you my preliminary list of responses for my question on an Alternative for MS Project.

I do not endorse any of these products yet, as I will be trying them over the weekend, but I will share my opinions once I have. Additionally, if you have any suggestions that are not on this list please share. And if yours is one of the suggestions on the list, please explain why you suggested the product, since you have more than 140 characters to do so.