don't by that beauchat stuff, not worth it. Also remember MOST dive gear is OEM'd by other companies. In the list below, most all of it is manufactured by a handful of people in Taiwan.
Regs: I would avoid used, and get the Dive Rite XT set I linked on the other thread. $700, write it down
BCD: Deep Sea Supply singles rig, likely the SS plate in whatever size you need, and LCD30 wing-$500, write it down
Suit-keep the wetsuits you have, but get a USIA suit, they're made an hour north of Portland OR, are very high quality, and about $1500 with pockets, P-valve, custom cut etc.
Computer: I hate the Zoop, it's useless-http://deepblu.com/COSMIQ.html it's $300, new to the market, but has had some positive feedback so far. Otherwise, buy a used Petrel for $400-$500. With that DeepBlu out right now, I wouldn't consider any other computer than those two.
Dive Light-http://
www.caveadventurers.com/explorer-back-up-lights.html Don't buy used lights, they're not worth it unless you're buying a canister. These are fine, they throw a lot of light, aren't too expensive, and have an indicator LED on the button to tell you approximate battery life. They'll likely give you a bit of a break if you buy it with the regs, just call them.
Knife, just get a trilobyte or a bench made 7 safety cutter. Don't need anything else. Benchmade will hold up to salt better and doesn't have a blade to replace, but the Trilobite is $25 with cheap blade replacements
Cave Adventurers - Eezy Cut Trilobite Line Cutter - Marianna, Florida USA - Never Undersold!
Accessories-SMB should be ordered with your BCD from Tobin, I like the black gear bins from Costco with yellow lids for $10, get 2, drill holes in the bottom of one, and set it inside the other, keeps the water out of your stuff.
Force Fins: I'm not a fan, they're annoying and require you to develop a new kick technique for technical diving, Hollis F1 would be my recommendation for backmount diving in a drysuit
Snorkel: don't need one, but if you want one, just buy the cheapest snorkel you can. You're scuba diving, not snorkeling, and a simple $5 j-snorkel will work just fine
Mask: you don't need a super expensive fancy mask, Dive Gear Express has some nice ones for cheap. My current favorite, and every bit as good as my atomic for $25
DGX Ultra View Frameless Mask | Dive Gear Express®
Probably looking at $2k for everything except exposure protection, with a new bc and regs. Can probably save a few hundred bucks if you are patient and buy used, but not going to save a whole lot.