How much flow you want in a tank will depend on what corals you want to keep. Softies and LPS generally require less while SPS corals generally require more/higher flow.
For higher budget solutions, both Vortech and Tunze are options. For a 200 gallon tank, 2 x MP40W (vortech) or 2 x 6105 (tunze) would be a decent start. Either of these routes would be my choice.
For the budget minded buyer, there are brands such as Hydor Koralia or CoralVue High Seas. Either of these brands will get the job done, but they tend to compromise looks, reliability, or amount of flow depending on what aspect you're comparing.
Jeff