Since it also acts as the interpreter, you can't get around using the QBasic editor. One convenient thing is that when you edit a program within the QBasic editor, the change is right there ready for the "Run" command. If you use an external editor you have save the changes and reload them into the QBasic editor before the program can be run.

My own suggestion is that you use the built-in editor only for short programs, perhaps 50 lines or less. Or, use the editor for making minor changes to an existing program.

Text Editors
When it comes to writing much larger programs, however, I definitely recommend you find another text editor and accept the penalty of reloading the file into the QBasic editor.

Many programmers use NotePad, the free editor that comes with Windows. I personally use NoteTAB more than any other text editor. I like it's tabbed interface, ability to open multiple files and option to re-open all files each time the program is restarted.

However neither NotePad nor NoteTab provide syntax highlighting, which is an extremely useful way to view code.

So despite my own preferences, I recommend that you use one of the following syntax highlighting programmer's editors from the following list.

Programmer's Editors
Programmer's editors primarily provide syntax highlighting for source code. They also can include capabilities for code generation, error detection, custom formatting, API access, debugging, script testing, and much more.

The list below identifies several of the more popular programmer's editors, suitable for creating or editing QBasic source code files.

All of these tools will meet your QBasic editing needs, but I recommend using ConTEXT, which comes with a QuickBasic language definition file and is suitable for immediate use with QBasic. All of the other editors can be set up with QBasic syntax highlighting (see the respective users manuals), but creating the language definition file can take some time.

Freeware:
• ConTEXT
• Crimson Editor
  
• Notepad++
• PSPad
  

Shareware:
• MultiEdit
  
• UltraEdit
  
• SlickEdit
  

Expanded Programmer's Editor List
In addition to the recommendations above there are literally hundreds of other editors available. If you want to see more options, take a look at my complete list of available editors.