You should consider packing the JustDecompile.exe and all of its dependencies into a single assembly file.

Here are some of the advantages for this:

-Much easier (xcopy) deployment.
-Startup time improvement
-This will open the way for autoupdating without requiring the user to copy any files (Reflector style)
-Can have a convenient portable version of the tool

It is all about convenience...

add a C#/IL and VB/IL dual view where the C# or VB source is shown but below each C#/VB source line the IL asm code it consists of.

Allow two libraries to be loaded and compared. Postition the assemblies side by side and allow dynamic drill down into the tree.

The export of an assembly to a project doesn't reflect the assembly attributes -- even though they are visible in the GUI.

It is an open question whether the created source should list the attributes in some fixed order (alphabetical, or -- my preference -- based on someone's subjective idea of what their importance is) or if they should be exported in the sequence they're encountered in the assembly. (It's hard to know why they would be in a different sequence in different versions of the assembly, but that does seem to happen.)

Every time I start JustDecompile, it is positioned halfway down the screen. It would be nice if it remembered the screen size and position.,

The current version puts braces ({}) on their own line. I want the opening brace on the same line as the initial keyword.

if (a == b) {
not
if (a == b)
{

A nice option is to pick up all these formatting rules from your Visual Studio settings

The pack:// Uri scheme is pretty hard to get right. It would be nice if you could construct this Uri for accessing embedded wpf (or any applicable type, such as images) resources. Creating them for use within the same assembly, and from without, would be awesome.

Decompile the ressources from the assembly to the project too

Add the option to search msdn when you right click an item.

As JustDecompile is going to always be free, I don't think it would be unreasonable for you to make its source code available too (or maybe just the parts of it that would not dangerously expose the implementaiton details of your non-free products). It would be very useful for many of your users to see/study how managed code decompilation is performed and maybe even tweak it in minor ways so they could easily implement their own formatting/refactoring preferences etc. You know, the general advantages of open-source software.

When you open an assembly and there is a referance to another assembly that is not loaded it should prompt you for the location. Take a look at .NET Reflector

In the decompiled output, when displaying a generic type with a concrete implementation, both the generic type and the concrete types should allow navigation. For example, currently, clicking on List<string> takes you to List<T>, but you cannot click on the "string" element to go to that type. In other words, the current interface only creates a single hyperlink (to List<T>) and not two (one to List<T> and one to the concrete type). This concept should be extended to allow for arbitrarily-deep nestings, such as List<Func<T, string>> creating links for List<T>, Func<T, K>, and string.

ILMerge was used to build a single file assembly from our code and a multi-megabyte assembly provided by a third party. It's desirable to be able to compare two versions of the resulting merged assembly. As things are now, only the entire assembly can be exported. It would be nice to be able to export from any node -- by far the majority of the 1000+ files resulting from an export are from the third-party library. I'd like to be able to export only "our code" from the assembly.

When i select all code and copy paste them into outlook then the line breaks are missing..

In addition to the current framework versions, may I suggest Micro Framework and XBoxLive (Phone7) framework profiles?

Everytime I navigate back from where I came from (or forward to where I was), it navigates to the top of the page. It would be nice if it would remember where you were in that code page.

As an example, rather than searching for Timer and looking through the list for System.Windows.Forms.Timer, someplace I could type in System.Windows.Forms.Timer and have it take me there. It's usually easy to just click through the tree to find the class you want, but sometimes namespaces are hidden in different places, such as how System.Windows.Forms is in its own .dll father down the list than the main System .dll is.

Best feature was to decompile not only in IL Syntax, but also in VB or C# Emit calls

.Emit(OpCodes.Ldarg_0)

C# has create Project same can be visual Basic also
so that it can help VB developers