Hi,
You can use C# to create your own modules and use it in dnn. if you want to see a working module of it see my site
http://www.skmtech.com/Portal01/GetInspired/tabid/56/Default.aspx
Its an inspirational quotes module. Completely written in c#, works like a charm.
I Think DNN is by far the best in terms or community / doc / great forum support and the confidence that other major players are using it.
Yes its done in vb.net and i too was skeptical at first and to tell you the truth very very hesitant.
After 4 portals and few more in the pipeline, i think i wasnt wrong at all.
Recreating this thing is going to take anyone years.
So why not re-use / re-cycle ?
Remember "good developers code, better one's re-use"
Come on jump right in. its fun