And the winner is... Stylet!

src/Artemis.UI/ViewModels/HomeViewModel.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Diagnostics;
+using Artemis.UI.ViewModels.Interfaces;
+using Stylet;
+
+namespace Artemis.UI.ViewModels
+{
+    public class HomeViewModel : Screen, IMainViewModel
+    {
+        public string Title => "Home";
+
+        public void OpenUrl(string url)
+        {
+            // Don't open anything but valid URIs
+            if (Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute))
+                Process.Start(url);
+        }
+    }
+
+    public interface IMainViewModel : IArtemisViewModel
+    {
+    }
+}

src/Artemis.UI/ViewModels/Interfaces/IArtemisViewModel.cs

@@ -1,10 +1,7 @@
-using ReactiveUI;
-
-namespace Artemis.UI.ViewModels.Interfaces
+namespace Artemis.UI.ViewModels.Interfaces
 {
-    public interface IArtemisViewModel : IRoutableViewModel
+    public interface IArtemisViewModel
     {
         string Title { get; }
-        string Icon { get; }
     }
 }

src/Artemis.UI/ViewModels/MainViewModel.cs

@@ -1,36 +0,0 @@
-using System.Diagnostics;
-using System.Threading.Tasks;
-using Artemis.UI.ViewModels.Interfaces;
-using ReactiveUI;
-
-namespace Artemis.UI.ViewModels
-{
-    public class MainViewModel : ReactiveObject, IMainViewModel
-    {
-        public MainViewModel(IScreen screen, ISidebarViewModel sidebarViewModel)
-        {
-            HostScreen = screen;
-            OpenUrl = ReactiveCommand.CreateFromTask<string>(OpenUrlAsync);
-
-            // Add this view as a menu item
-            sidebarViewModel.MenuItems.Add(this);
-        }
-
-        public IScreen HostScreen { get; }
-        public string UrlPathSegment => Title.ToLower();
-        public string Title => "Home";
-        public string Icon => "Home";
-
-        public ReactiveCommand OpenUrl { get; }
-
-        private async Task OpenUrlAsync(string url)
-        {
-            await Task.Run(() => Process.Start(url));
-        }
-    }
-
-    public interface IMainViewModel : IArtemisViewModel
-    {
-        ReactiveCommand OpenUrl { get; }
-    }
-}

src/Artemis.UI/ViewModels/RootViewModel.cs

@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+using System.Linq;
+using Artemis.UI.ViewModels.Interfaces;
+using Stylet;
+
+namespace Artemis.UI.ViewModels
+{
+    public class RootViewModel : Conductor<IArtemisViewModel>.Collection.OneActive
+    {
+        public RootViewModel(ICollection<IArtemisViewModel> artemisViewModels)
+        {
+            // Add the built-in items
+            Items.AddRange(artemisViewModels);
+            // Activate the home item
+            ActiveItem = artemisViewModels.First(v => v.GetType() == typeof(HomeViewModel));
+        }
+    }
+}

src/Artemis.UI/ViewModels/SidebarViewModel.cs

@@ -1,23 +0,0 @@
-using System.Collections.ObjectModel;
-using Artemis.UI.ViewModels.Interfaces;
-using ReactiveUI;
-
-namespace Artemis.UI.ViewModels
-{
-    public class SidebarViewModel : ReactiveObject, ISidebarViewModel
-    {
-        public SidebarViewModel(IScreen screen)
-        {
-            HostScreen = screen;
-            MenuItems = new ObservableCollection<IArtemisViewModel>();
-        }
-
-        public IScreen HostScreen { get; }
-        public ObservableCollection<IArtemisViewModel> MenuItems { get; set; }
-    }
-
-    public interface ISidebarViewModel
-    {
-        ObservableCollection<IArtemisViewModel> MenuItems { get; set; }
-    }
-}