Great questions and thoughts.
The distance is going to determine a couple of things:
- The type of fixture that will work best
- The amount of spill (the light that hits unwanted parts of the background). This will also be determined by the light fixture's height.
If your fixtures are further than about 20', then nearly always ellipsoidal light fixtures will work best. They will give you the most consistent beam spread (least amount of hot spots or fall-off) and will give you the most control over where the light hits and where it doesn't.
Here's an example of an ellipsoidal:
If your fixtures are closer than 20', then you have a few options depending on priorities and budget. Best option is usually fresnel studio fixtures. They will give you a fairly consistent beam spread and a bit of control of spill using barn doors. Next best options are "PARNels" or PARs. A PARNel takes some attributes of a fresnel but puts it into more of a PAR fixture - this gives you some control like a fresnel while keeping the cost down. A PAR can come in different sizes and shapes, and they basically just barf light everywhere with not a lot of control over beam spread or spill.
Here's an example of a fresnel with the lens open:
Here's an example of a PARNel:
Here's an example of a conventional (non-LED) PAR:
You can also get all of these types of fixtures in either conventional (tungsten or halogen bulbs) or LED.
If you can let me know what type of budget you're expecting to work within then I can help you narrow down your best options.
If your budget is pretty tight, then I would suggest checking out UsedLighting.com for some good quality used fixtures and dimmers.