FW to SW transition, equipment suggestions

I have had 3 successful freshwater tanks for about 3 years (10G, 29G,
and 55G), but I've been seriously considering converting the 55G tank
to a reef aquarium. Everything that's in there can be moved to another
tank, with the exception of a single pl*co that I can probably give
away locally. I know that I'll be much happier with the appearance and
experience, and I've been researching the time involved, cost, and
types of fish and coral for some time.

The only downside is that everything (literally) will have to be bought
online, because I have little faith in my LFS. Obviously, I'll be
stripping down the entire tank, and will start with LS and LR until
everything is nice and stable... I'm in no hurry.

I'm hoping that you guys can advise me on the equipment I need to
purchase before getting started. I currently have a Magnum 350 canister
filter, but that's it. I think that I will need to change the lighting
(although I don't know what to change it to), but I'm not sure about
what other equipment will be needed.

TIA,

Jason