Can I recommend a skimmer?
We have a 220g Coralife Super Skimmer on our 75g reef tank right now and about to put one on our 90g fowlr.
I've heard they're not as efficient as the bakpaks but they're very simple, and as a beginner I think that's pretty important. We just got into saltwater and have had no problems with it, and I know quite a few fish stores that run them on their sumps.
They come with everything you need to run in, and you can run the waste into a bucket so you don't have to worry about the cup overflowing.
Also, I agree that a cleanup crew helps A LOT. So if you're gonna keep fish that won't eat your cleanup crew (like the trigger in my fowlr tank, hehe) then it would make your life a lot easier.
Btw, you don't absolutely need a sump, but if possible, I agree with brenden, that's the best idea. Skimmers look pretty ugly on the back of a tank, especially larger ones, and take up quite a bit of room. Extra water volume is also a nice thing to have, just like in FW.
And yes DON'T overlook the powerheads. Powerheads are even more important in SW since SW doesn't hold as much dissolved oxygen.