Recently, I came across Mono and MonoDevelop packages in Ubuntu linux. They claim to have a .NET runtime in accordance with CLI. Before installing the packages myself, I would l
I use WinForms in mono. The 2.x releases are very good.
I develop forms in visual-studio on windows, and run them in Linux, with zero code changes. Yes, forms look a little different than on XP, but then again, an XP-themed GUI would look kind of strange in GNOME.
If you are just getting started, stick with WinForms, while you get comfortable with Mono/Linux. However at some point you might want to investigate GTK.