Connecting to ArcGIS Desktop PostgreSQL database (running locally)

I know this is a total noob question but then again, when it comes to PostgreSQL I am a total noob...

I have installed the OpenGeo suite on my computer, running Windows 7, 64-bit. I have downloaded the tutorial data and have been working through it. I would like to access the database that I have made with ArcGIS so I can start learning about how that works. However, when I try to connect to the database using the "Add Database Connection..." I can't seem to figure out what to put in for 'Instance' - everything I've tried (localhost, localhost,54321, my IP address with and without the port, my computer name) doesn't seem to work.

I installed and created the nyc test database according to all the instructions in the OpenGeo tutorial pages but am at a total loss here. I know this must be an easy thing to deal with, I just can't get my head around it. Can someone with more experience throw me a bone on this one?

Frustratingly enough, QGIS connects to the database with almost no effort and everything works fine - but my organization is heavily ESRI focused and switching to QGIS is a long shot...

EDIT Thanks everyone for pitching in on this. I really appreciate the advice, it's what makes this site great. I have installed

• OpenGeo Suite 3.0.1 with no extensions


• ArcGIS Desktop 10.1, no license for server

I just went to the Opengeo website and downloaded the Windows installer and installed the default configuration. I have tried every permutation for the instance name that I can think of - using colons and commas, my machine name, localhost, postgresql, server, my IP address, random curse words, anything I can think of. I have been using port 54321 instead of 5432 because that is what the OpenGeo workshop told me to set up my 'nyc' practice database to use.

It seems that localhost should work, here is a shot of the server properties from pgAdmin:

Answer

The problem here was that I had not installed the client files, so I couldn't connect to the database.

Rookie mistake through and through.

I copied libeay32.dll, libiconv-2.dll, libintl-8.dll, libpq.dll, and ssleay32.dll from the PostgreSQL folder and put it into the ArcGIS10.1 \Bin\ folder. Then it would connect up just like it should.

Thanks for all the help on this!