Your best bet is to try and find someone willing to buy the entire tank (contents and all) for a set price. This will involve the least amount of work for you with regards to the flood of emails/pms/phones people claiming about being first and what not. Then let everyone else who wants a "part" to wait in line/queue until you decide you can't wait for a buyer to buy the whole thing.
A crappy picture will reduce the price of the item significantly. Whereas a great picture will create interest and possibly a line to buy the item. I think one thing people don't realize is that if you are serious about selling, a DLSR and a photo-top-view box are helpful in making sales.
Tunze products are typically always in demand - especially if you can show they are still under warranty, which gives an indication that the equipment is new. If you still have the original blue boxes for them even better. Typically people sell these in sets (e.g. two 6055 with multicontroller etc.).
in my opinion 2k for the 120 set up is too much. You'd have to explain exactly the models of skimmer pumps, ato etc.
In the end you may be better off segregating the live goods from the dry goods. The live stuff (fish) will have to go at a huge discount in my opinion. Or be sold/donated back to the LFS. The corals should be fragged sold shipped.
$800 for the breeder doesn't sound as bad to me but it depends on what the contents are. if you cleared out all the high end corals and it's just LR and some fish - I'm doubtful you'll get that price. Also watch the tang police 2 YT in a 40B is not the thing to be advertising out these days...