Always learning, or else there is no point.
Hey Mike, something not mentioned yet is the use of anamorphic lenses. Sometimes you can benefit from more detail/information using an anamorphic lens or adapter. Depending on the camera you're shooting with (if it can shoot 4:3 aspect ratio, or if you're in 16:9), you can use a 2x or 1.33x anamorphic lens/adapter. What this will do is squeeze your image and maintain ALL of the detail. Why is this kind of cool? Because instead of cropping your image to 2.35:1 in post and losing detail, you actually stretch or squeeze the image in post to 2.39:1 (basically 2.35:1) without losing any pixels/data/information. These lenses also create horizontal lens flares and different shaped bokeh, which adds to a "cinematic look" as many directors shoot feature films using this process (anamorphic). Granted, they use VERY expenses lenses ;). But you get some fun adapters on eBay to create this effect. Just research it a lot...have to know the right one to buy.
That being said, if what you're shooting is mostly to be viewed on a TV or even online, for a client, etc., ain't nothing wrong with 16:9. Probably your best bet. Just personal preference and how you want people (and yourself) to view your work. Try both out, see what you like best. I think you'll find yourself switching between the two dependent on your work. Hope this helps!