I've chosen to use BlogEngine.NET as my open-source blog engine of choice. This was by no means decided on in any scientific manner at all. I basically just checked out all the open-source C# bloggers at http://csharp-source.net/open-source/bloggers and had a look at their homepages.
The only 2 that really took my fancy was DasBlog and BlogEngine.NET. Downloading and examining the source packages for both led me to believe that BlogEngine.NET was likely to suit my needs better. All that really means is that it looked simpler :P
I'll follow up this post with some more motivation once I get this running on Mono on my Ubuntu server. Currently I'm writing this from the relative safety of Visual Studio on my windows box. I'll let you know how it went shortly (if i'm lucky)!