I really like the strawberry chocolate wall and floor! I have it in my main room right now, but none of my furniture really goes with it. I’m desperate to have the Gracie sweets series back—or something like it at least.
I love the Butterfly Wall from the bug catching tournament! It's so delicate but pretty. I originally had it in my attic but moved it to my main room since I wanted to see it more.
I also love the Kisses Wall (in my avatar). It doesn't match anything else in my house, but I LOVE vintage glamour things like it.
Both of those wallpapers I'd literally use in my own, real home.
Not sure about flooring, though... there's so many good ones that none stand out as the best for me!
If I had no self-control, I'd slap the cityscape wall onto every room of every house on my island. But I remember the CCTV wall flashed me when I first got it and saw it in-game. So much so that I immediately came up with a whole new character to justify using it. Same goes for the laboratory one and the one with all the servers.
As for flooring, the ones containing water are all really pretty, but you can hardly ever use those. For simple "this is a real home"-type rooms I almost always fall back on one of the light wood floorings. They just look the best
I like the painted board walls for realistic rooms. The stormy night wall is awesome, and a friend has used the butterfly wall with white rattan furniture that looks incredible.
My favorite wallpapers are the Cityscape and Stormy Night ones. I actually quite like the fireworks wallpaper as well. For flooring my top three in no order would be: Imperial flooring, Cloud flooring, and Fireworks flooring
I like the arched window wall and cafe curtain wall since they make it look like the room has lots of windows. My least favorite is the classic library wall because it doesn't have windows. Libraries normally have windows and are not that gloomy. For floors, I love the dark parquet since the squares make it easy to place items.
The ice wall and flooring of the frozen set and the mermaid wall and floor are also so pretty and look great with their furniture.
my favorites are probably the underwater ones! they're just so mesmerizing since we never had animated walls and floors before :0 I noticed the other day that they splash too!
misty garden wall + jungle flooring is a nice combo and that's probably my favorite wallpaper of the lot. i tend to favor the "plainer" floorings though, like all the painted wood or plank ones.