If you tired with Task form with default like this.
You can customize your task form look like this.
How? follow this instructions:
1. Assume you have libary like this.
Add New Item in Visual Studio, in my case my ContentType is “CustomContentType1” and Remember (just copy paste in notepad it will help 😛 ) ContentType ID. in elements.xml
2. In workflow task list, in my case i have create new workflow task name with “WorkflowTaskListC”, goto to ContentTypeBinding in elements.xml and replace with your new content type ID to elements.xml in ypur workflowTasklistC
3. Add new SharePoint Layout Map Folder and Add Application Page
And you have new application page, like this.
4. In ApplicationPage1.aspx, you can do anything you want just like regular aspx page in visual basic or c#.
and also in code behind you also can use visual basic or c# code to retrive or set value and anything you want.
5. Just publish the solution and you have Customize task form in your workflow approval.