I do mostly architectural images and it is often very important to my clients that I get the reflections in the windows to be very accurate. An example would be a ski area home where I am looking at the house but I need the mountain perfectly placed on the living room glass. Pylon has given me the solution to this by creating a plane outside the view area that has an HDR image of the reflection set to be an emitter material using a value of about 8. While this does work it also about doubles my render times and leads to a lot of trial and error test renders to get the reflection right. I have also tried to use an IBL light in my scenes which has great results from a lighting standpoint but I can never get the reflection to show accurately in the glass. Putting a value other than 1 in the azimuth or altitude crashes the program instantly. I have also tried to put the reflection on in photoshop but that is always tricky since there is a fair amount of transparency in the glass and it leads to some unrealistic results.
I am curious to know if anyone has come up with another workable solution to this issue.