In case you care (I'm not sure why you would, but anyway), we decided to go with side-by-side, because it looks like we can just barely fit them. And that also lets us re-use the ones that came with the house, which means a top-loading washer. (Which allows me to try felting, a big plus for top-loading over front-loading.) Which means no putting a shelf right above them, but really, that's just for fancy anyway, because there's nothing really wrong with folding on top of the machines themselves, as long as you keep them lint-free. Which will be easier to do with a utility sink right there. We might add a fold-down shelf too, but I'm honestly not sure it's necessary. And there will be a bunch of nice storage shelves above the machines. It won't look super-fancy and designer, but you know -- it's a laundry room. I can live with that.
So right now, left to right -- 20" laundry hamper under chute, 22" utility sink (model still TBD, and if you happen to see a nice one with stand included for a reasonable price, do let me know, because somehow the whole process of choosing a separate sink and washstand / vanity is more than my little brain can handle right now)), side-by-side top-loading washer and front-loading dryer.
If we hate it, we can change it later, and move these machines down to the basement for supplemental laundry, since there are currently no machines planned for down there.
Phew. Good to have the decision made. I'm sure you were all biting your nails about it too.