I think for the most part, the hobby and hobbyists are leaning towards LEDs. Its starting to be difficult to find metal halide fixtures, when you can buy a decent LED unit fr the same price.
Powerheads. If your looking for wave action, you have a few choices. Ecotech vortech mp series, tunze variable speed powerheads, jebao wp series, and then there are squirt gun mode, like maxijet hydor oscillators. Each have their pros and cons.