I am torn between PostgreSQL and MySQL. I am forced to install the chosen one on Windows. I especially need ASP.NET Membership and NHibernate as well.
I've recently gotten MySQL with NHibernate and Asp.Net Membership working without too much hassle. Check out this related post: http://stackoverflow.com/questions/1185187/accountcontroller-using-mysql-in-asp-net-mvc.
PostgreSQL is clearly the technical more advanced database managment system, while MySQL is probably a bit simpler to run, is more widely used and in consequence offers more support sources on the internet.
(I am a PostgreSQL user.)
AFAIK either one of them should work fine if your requirements are fairly low. If you want to use more advanced db stuff, PostgreSQL is probably the better choice, but for simple stuff it doesn't really matter.
My recommendation is to pick the one you have experience administering, or that is used elsewhere in the organization.
I would recommend PostgreSQL too. It´s more robust and offers a lot more (triggers, custom types, etc) than MySQL. Last time I looked in MySQL (4.x) there´s nothing of this.
Here at work we choose PostgreSQL for our intranet software 4 years ago and we are very satisfied.
An interesting article/wiki on MySQL VS PostgreSQL that might help in your decision.
Disclaimer:
I have no previous experience with WikiVS prior to now and little with PostgreSQL in general - but the article certainly seems well written...I'd be interested in knowing how well balanced this is for future reference.
Any experts on MySQL or PostgreSQL that can validate/refute the content?