Again, there are many nice cameras out there, but I haven't heard a compelling argument for buying anything that you don't have already. Why are people so stressed about what gear? It really doesn't matter what you have. Once you have a few nice lenses and a decent body, you should be set for a decade or more, unless you're a journo, who wants a 2nd body for insurance and to avoid constant lens swap. Just ask yourself what you're actually unhappy with in your camera and then make a decision. Are you going to take better photos with the 5D MkII? Unlikely.

Many pros continue using the 5D (e.g. David Burnett) and 5D MkII. Nothing wrong with them. Comes down to price, comfort, reliability and useability.
My best photos are usually taken with a camera I am completely at ease with. If that means continuing to use a 6 year old body (or in my case much older gear) then there really is no argument, just consumerism at the other end. If you haven't got a DSLR yet, then it doesn't matter much what you get. Interestingly, but perhaps not surprisingly, I find pro-bodies often easier to use. However, they're usually not lightweight. So, more often than not, I just grab an old low-end consumer body and one lens, unless on assignment.

Irfanview is an excellent and free batch conversion program. Doesn't have a Mac version though. Of course it does make some sense to store jpegs as tiffs, but only previously unedited ones at that and If you want to edit. For professional editing/publishing purposes we've done this for decades.

I bought the D800e and a D600 as a back-up.
The D600 (now D610) is actually just as good, i.e. in real-life better.
That aside; my favourite lens combo is: 16-35 AF-S, 50 1.4 AF-D and 70-200 2.8 AF-S. Throw in a 135 2 DC if you need to and you can deal with any general digital photography out there, bar some sports, true architecture, or extreme macro.
People after do-it-all lenses usually don't need do-it-best bodies; the lens/body discrepancy will become obvious.

They're all fairly tough design wise; even my old D40. that one fell in the ocean for a millisecond last year; I pulled it out by the strap; the kit lens was wet/cactus, the body is still shooting fine. Just in case, I removed the battery and dismantled the body partially a day later, then put it back together.

A lot of teleconverters hate slow lenses as well. I have an old Kenko 2x and AF only works reliably on my F2.8 or faster lenses, but I don't want to generalise too much; that statement isn't true across the board.
In many cases, cropping a bit is actually easier....
Anyway, we all know that the image quality with converters varies from lens to lens. Some combinations are excellent, others are crap; but even stacking converters can give decent results and is fun, although manual focus is the preferred modus operandi there. Buy one secondhand and if you don't like it...sell it on without much loss. Put it all together carefully, as done don't physically match, but I've tried over 100 combos over the years and never had anything damaged (and I don't want to overstate the incompatibility either, almost all consumer lenses are actually totally ok). A lot has been written about these things on the web. Trying out stuff is fun of course, but most manufacturers have incompatibility lists anyway. Using a TC with a wide lens is a rubbish idea in most cases anyway. (One exception, I've put a TC-16a between my Samyang 8mm MF fisheye, turning it into a 13mm full frame AF fisheye that works on my F4 and underwaterhousing combo!)

Image quality wise you won't see any difference on a D610 either (not that this is important anyway). Plus your computer has a better chance handling those files. But its your money.

I totally love the 17-35. Have had it for over 10 years. My most used DSLR lens.

Probably true to a point, optically, although you'll loose a bit of fore/background isolation and speed....and that's also true for the f4 version in both MF and AF.

Or e.g. 16/17-35, 50, 70-200.

My 13-year old (non-CF) Manfrotto 055 has been in the ocean/beaches/creeks (even a few times underwater e.g. for upside down shots of sea-ice) on many occasions. Rinsing it off seems to work; when it has been submerged/dirtied beyond the lower segment, I take it apart, rinse everything and dry it off. Sand is mechanically a bigger issue than water, no matter what material you use. Capped PVC tubing works great, too. - Codoms break, sissies :) and make you look like an idiot in that situation.

You guys are so serious about stuff :). - Still silver bullet chasing with DSLRs and their lenses? To annoy some and "help" others:
Those are of course perfect for images where speed/decisive moment/quantity is a factor, ie. 90% of photography; but if you are pixel peeping (which has of course little to do with photography as a creative outlet, nor the inherent quality of the image), your top of the line DSLR Lens combo is of course far from the "best" system for static subjects from a technical (or even contemplative) point anyway.
PS: (And back to the original question): Sure, I find my 17-35 AFS is still my most used DSLR wide. Its 10 years old now, looks like its been to a war zone once too often, but helps me take excellent images and I'll use it till its too uneconomical to repair, i.e probably for another 10-20 years; I'm sure the 16-35 would do fine, too. - I only use primes in formats that don't offer zooms, or when I really need that shallow DOF (or if having a physically small kit is an advantage).

For static subjects and on a decent tripod: No problem at all.

For anything else...: A fast AF and VR/IS really helps in most situations tremendously.

Wow, another clanger in one day.....

The 85mm f1.4 Bower, Rokinon, Samyang, Vivitar (same thing) is sensational. I haven't tried any of the other focal lengths they're making (am contemplating trying the 8mm with my TC-16a on my F4 as a full-frame fisheye in an underwater housing....). But their optical designers know what they're doing. Are these budget lenses: Of course, but some are very, very good.