You know, I hadn't looked at Lan-Li's site in a while. Those mATX
Mini-towers with the optical drives mounted sideways are pretty wild, in a "Centre Pompidou" kind of way.
I agree -- you've got two audiences here with very different preferences. Enthusiasts who regularly add and swap components are going to want standardized components and a case that's comfortable to work in; ordinary users want something small and convenient to use because they'll never crack the case (though if they ever need to get it repaired they'll want standardized components, that's not something that usually goes into a personal buying decision as proprietary Dell desktops have shown).
Shuttle demonstrated there is a huge untapped market for small, stylish systems; the problem was that they didn't use standardized motherboards and PSUs, so they were expensive to build, upgrade, or repair. This is why DTX actually has a chance: unlike BTX, it offers something users (as opposed to enthusiasts/builders/OEMs) can actually see and appreciate: smaller systems at reasonable prices.
I don't agree that an "all-in-one" iMac style machine is necessarily the way of the future. There is a niche for those, but the problem is that the
one option even the most unsophisticated user decides on separately is the monitor. Any CPU may be fast enough, any HD may be large enough, but they're going to have an opinion on how big they want their monitor -- or how much money they want to spend on it. And it's the one thing they might change later, because they don't have to pop the case to do it. Now, I could see a low-profile system that has a sort of piggy-back VESA mount, so you could use it to replace an LCD monitor stand (hmm, I should probably patent that design idea...). But I think you'll see more and more "Mac Mini" size systems for office use (and the upright equivalent -- the knock against those has always been the optical drive ends up vertical, but these days a lot of IT depts would rather not have any removable storage in client systems anyway -- it's just a way for secrets to leak out and viruses to leak in). And more "pizza box" style low profile HTPC cases (though there you have the issue of limiting yourself to integrated graphics, unless you have a funky right-angle connector for the GPU) which would also fit neatly under an office monitor.
If DTX takes off (and it's far from a done deal), I would expect low-profile / SFF systems to cost no more than an equivalent desktop system -- and if that happens, you shall know the geeks by their "big" mini-tower cases (just like you can tell them now by their racks or full towers). Everybody else and their mothers (especially their mothers) will be running little low-profile systems.