Actually most of our Dedicated Servers are running CentOS, some with Ubuntu and only a few with Windows (SBS i think?).
We've played around with OpenSolaris and we do offer it as a choice of OS to our customers, but the interest just isn't there.

Yes, most of the hosting companies use CentOS. It is very good for web server.

My company has switched over 2 server companies due to probelms. But i could say that instead of having it on your own, a colocation server would do the job in a better way. There were so many advantages and also it was less expensive. And Dell offers a good service too. Hp is equally good. I would like to give the technical experience in about a month's time as i will get an exposure over that.

hi molly, can you describe in detail..what are your requirements and what is the problem you are facing...

I like the question about running solaris or windows. I find that the stability of windows really is not the best and would like to know some of the other options available.

Windows server is not a terrible OS to use depending on the application and how well the Win administrators maintain the environment. I personally would never deploy a Win server in my network, but a lot of businesses do because that is what people are more familiar with on the user level. Also there are some corporate applications that will not run on anything but a Win server.

Where I am now we use Exchange for office email and run many other applications--controlled by other groups--to run services that are not available or compatible on Linux, AIX, or Solaris. Our Blackberry server software only runs on Win so we have to have BB servers built onto Win systems. The admins do a very good job in maintaining the environment so that it becomes transparent to the end user. So for a few things out there you cannot get away from deploying a Win server.

We are using HP and i think it can easily accomdate your further requirements. I request molly to kindly elaborate the requirements which cannot be fulfilled using HP.

Best startup hardware?
 

I am currently running a small DC and would like to know what the best start up hardware configuration would be. I am definately going to use HP gear, as they are our preferred manufacturer. But what is the best way to go with routers, control systems, etc. that you would use for your own DC?
I am a pronounced Dell hater, and will never be swayed that way. But IBM is something we never looked at.

Servers...
 

Most of our stuff runs on Sun servers. Mostly x64 servers for windows and unix/linux. THey are just very fast and very reliable. There are also some IBM Blades and Appro Twin Dual Proc. 1U Servers.

I think it depends on what you need. Sometimes you can build a scrapheap server and never need another one. Other times, only the top end ones will do. So figure out what you need first.