While I understand the "cool" aspect of having sharks in a tank in a bar, no matter how "small" the sharks, they should really be kept in much larger tanks. If you're going for the "wow" effect, then yeah... that'd probably do it. But if you're looking out for the well being of the fish, then leave the sharks to the big aquariums and the ocean. Obviously... just, my, opinion.
With that said... on to your original question! You will always get a more economical deal ordering online. Always. Even including shipping. However... I wouldn't buy a tank online. Dealing with LTL freight companies to get your tank delivered is a hassle most times, and if there's damage (high probability) it's up to you to deal with it. Better to spend a little extra $$ and buy the tank from a local fish store. There's also the aspect of supporting your local suppliers, so you have to figure how much that's worth. But cutting out the middleman will always get you a better deal. Me personally... I bought my tank and stand locally - everything else online. Even my rock and sand. Fish have all been local, about 1/2 my coral local and 1/2 online.
Here are some of the online shops I've dealt with that I'd personally buy from. (I'm leaving out the ones I wouldn't...)
petsolutions.com (my favorite right now)
hellolights.com (for lighting... obviously)
drfostersmith.com (used to be my favorite, but seems to be having shipping quality issues lately - but haven't used in a while)
I have a feeling I'm missing some, but this will at least get you a starting point.
Regarding a checklist of what you'll need, it's probably better you do some research on what type of tank you want to keep (reef? predator?), make up a list of what you think you need, and let us knit-pick it!
But seriously... I've always found that you learn more if you make yourself do the research than have someone spoonfeed you the answers. And it sounds like you're not adverse to researching! For example... I lurked on this site, pouring over threads for three months before I bought a single piece of equipment when starting my tank!
Also... while saltwater really isn't difficult, it can be time consuming to keep up a clean reef tank. I think many of us lose track of how much time in a week we spend in our tank... a little here, a little there... it all adds up. As a business owner, when you're at work you have other issues that definitely take priority over the tank. Having a tank at home for a hobby is one thing. Having it at work, and part of the daily grind is another thing. You might think seriously about having someone locally service, maintain, and stock your tank. Not sure if anyone near you does that type of thing, but it seems like there's always at least one saltwater tank servicing/maintenance place in each big town. While it might not give you the "hands on" you want, it may give you the same effect you're looking for, and end up costing you less when you factor in what your time is worth.