Ideal features:
We're currently using ASP.NET, which means you have to check out the website to make any changes (and so our front page has stuff from a year ago on it). Lame.
Can be free or paid. Any suggestions?
Just about any CMS can be run on Windows these days. A good starting point might be CMS Matrix.
I remember a while back PHP support on IIS got significantly better, so now there's no need to run Apache to have good PHP support on a Windows server. ASP.NET support is still strong, as well. MySQL and PostgreSQL also run just fine on Windows, and between MySQL, Postgres, and MSSQL, you should be able to support any off-the-shelf CMS. And any good CMS would allow you to theme it anyway you want - just take a look at various Drupal, WordPress, and Joomla! powered sites to see what people have done.
So, in short: any CMS can be run on Windows now. I've been involved with the deployment of a number of CMSes, but I would need to know more about your requirements to actually suggest a specific one. If you want to test, try them all. WordPress and Drupal are solid PHP based CMSes. The only ASP.NET CMS that I've deployed was .NET Nuke. And if you want to build your own, there are lots of good frameworks for every language.
So the specific questions to ask:
You can download and try Composite C1 - here is a blog post on installing it via WebMatrix http://docs.composite.net/C1/TeamBlog.aspx/2010/08/13/The-WebMatrix-experience you can also download it here http://docs.composite.net/C1/Getting-started/Download.aspx
It's ASP.NET 4 based but it's primarily it's XSLT features that give you great layout control.
There are short videos showing the user experience here; http://www.youtube.com/results?search_query=C1+starter+tip
If I were you, given that you have a software company, I would stick with an ordinary ASP.NET application with Master Pages and a SQL Server backend. I have found that a CMS causes more headaches than they solve. You mentioned you have to do a check out to make changes. So what? At work our content editors use Subversion to make editorial edits to our non-CMS Asp.net applications. Subversion is easy enough for editorial staff to understand and it allows them to have revision history. The only HTML tags they really need to learn are <p>, <br/>, <strong>, <em>, <li>, <img> and <a>. I would argue it is just as easy to teach someone basic HTML than to teach them how to use a CMS. Don't frustrate your star developers by making them have to work around a CMS.
If you are married to the idea, at my day job I use Sitecore which is a Asp.Net based CMS. It is very flexible for developers, but the learning curve is high and it costs several thousand dollars. I also hear great things about Dotnetnuke which is open source.
Even almost all PHP CMS will work on Windows Server, if you have some ASP.NET knowledge then I would highly recommend N2CMS. I tried DNN, Umbraco, Kentico, but N2 is far better in terms of simplicity of styling and modification (dev on new content types, for example products, categories). For db access it uses Nhibernate, so you can choose your dbase based on demand (sqlite,sqlce, mssql, mysql, ...)
It's free, easily styled (you can make it look like fogcreek just with HTML and CSS), uses standard asp.net master/content pages, MVC or WebForms pattern, it's multilanguage, multidomain.
At the time of writing this, I think it's the best .NET CMS for general purpose. All others (DNN, Ubraco, Kentico) are just to complex, without any added value IMHO. But MS-backed Orchard is closing fast. Only drawback of N2 would be small amount of skins. You have to make your own.
I have a CMS for IIS based on Classic ASP. It is very much cleaner and easier to setup than CMS based on other languages. In a nutshell it uses Classic ASP to create and edit .asp pages.
No database is required. In fact it was purposely designed to not rely on a database at all and instead creates static pages to minimise server resources and enhance download times.
The Tnymce online editor will create new pages and edit existing pages. Or you can download the pages and edit them locally in any text editor or html editor that won't corrupt the HTML. For example Frontpage will trash the code while older versions of Dreamweaver will be ideal.
Lookwise, it uses bootstrap and was designed for use as a Wiki site, ie: it is not a toy box like WordPress. It can be easily customised to enable multiple authors, etc.
