And this gets back to "what are you going to shoot" but I haven't seen too many filters on the list. Say a couple of CPLs, ND, grad ND filters?
I would go 5DIII (~$3000) if you need the AF points (action shots/personal preference), 6D (~$1,800) if you are primarily a causal or landscape shooter.
I'd go 24-105 (~$600) if you shoot mostly landscape and well lit scenes, or 24-70 II (~$2,100) if you shoot in lower light more often/prefer natural light photograph/tend to obsess about having the "best." If you are mostly well lit/outdoor scenes with the occasional natural indoor light photography, the 24-105 plus a prime or two (see below) should be a good combo.
I'd go 70-200 f/2.8 II ($2,100) if you shoot indoors or the 70-200 f/4 IS (~$1,200) if primarily outdoors.
Think about adding a 1.4xTC/2x TC ($500 each).
If you shoot birds/wildlife I would be adding the 100-400L ($1,600), 400 f/5.6 ($1,200), or the recent Tamron 150-600 (($1,069).
A nice set of reasonably fast primes are always good, Rokinon/Samyang 14 f/2.8 UMC is a good lens to give you an ultrawide/nightscape option for $300. But ultrawide is a beast of its own. To stay on a budget I'd likely go Sigma 50 f/1.4 Art ($950; to be released, but initial reviews are good with a potential AF consistency issue) or Canon 50 f/1.4 ($300) to start. Then figure out which scenarios you need primes and add from there. The EF 100 mm f/2.8 IS L Macro is great ($900).
Then at least one flash, the Canon 600 EX RT ($450).
Then I'd save at least $1,500 for gear you identify down the road, $500 for accessories such as a good pack/bag (Lowepro Flipside 400 AW is a good choice, ~$70 off ebay), $800 for filters (clear/UV to protect your front elements, CPL and then ND filters as needed), and $300-$600 for a mid-range carbon fiber tripod and ballhead. You may want to consider a smaller camera for when you don't want to carry this around, but I am going to assume you already have that.
Overall, I think people would gravitate toward calling the 5DIII, 24-70 f/2.8 II, 70-200 f/2.8 II, 2xTC, 600 EX RT, with B+W 77 mm and 82 mm CPL/007 filters as the "ultimate" basic kit, supplemented with a few primes, as needed. That is ~$8,500 without any primes, tripods, backpacks, macro lenses, "super tele" etc. But, a heckuva place to start, and perhaps finish.
So, it depends on what you want to shoot, but you can spend $10,000 remarkably fast. I am on a multi year plan. Each year I spend ~$2k adding to my kit. That will change as soon as I add a big white.
Good luck.
Edit:
Oops, my bad...I just realized this was a hypothetical and not an actual question....but what I would do is what I have done and is pretty closely outlined above.