Most folks who run reef tanks will tell you that live rock is all the filtration you will need, save for a skimmer. Most other things whether it be hang on or canister filters, or even filter socks in a sump tend to trap and build up detritus leading to nitrate issues unless they are changed on a pretty strict basis.
Many folks coming in from freshwater tanks make the mistake of sinking money into filtration rather than rock and circulation (powerheads). Nitrates are tolerated much easier by freshwater fish (they don't like them, but the numbers have to get higher to bother them than they do for a saltwater fish)
If it were me, I would focus on getting porous live rock (dry is fine, and cheaper), ensure I had decent flow in the tank (couple powerheads to keep water moving), and forgo filtration entirely, save for possibly a skimmer... which might even be unnecessary if you don't intend to keep corals, and keep up on water changes
Fair warning, it seems nearly everyone ends up wanting to keep at least _some_ corals.
If you know you don't want to go in that direction, that's great... if you have the possibility of corals in mind in the future, save yourself some time and money and start with a tank/sump/skimmer setup now. Even if you never move to corals, a sumped tank will give you the most options long term, allowing for things like an auto top off, or reactors to be more easily and safely added...
One last thing. Tanks with sumps can be expensive, and the idea of them overwhelming. Once you understand how to mitigate most of the failure possibilities, and realize you can probably drill and plumb it yourself, they get less scary. Those are topics folks here can help you cover... once you've decided which direction you care to go.
