I remember one BASIC, called RapidQ, which I really enjoyed playing with a long time ago (which was freeware, but unfortunately I think it stopped being maintained as the source was sold to another company).

It had a rather cool graphical interface to create GUIs, kind of like VisualBasic I think.

It even had APIs to interface with DirectX.

Pic of what the IDE looked like: http://basic.mindteq.com/Screenshots/RapidQ.jpg