A variable speed pump certainly offers flexibility and allows you to minimize energy costs. However, because of the up front cost, they are not always the most cost effective solution. If you have a small pool and low electrical rates, a two speed will usually have a lower lifetime cost than a VS. With larger pools and high electrical costs, then a variable can make sense.

But again, if you are looking for the flexibility of VS and you don't care as much about lifetime costs, then a VS might be a better solution. If you go that route, you might consider an Intelliflo VF which allows you to directly set the flow rate instead of RPM so you wouldn't need a flow meter. It also has it's own timer settings.