I like the large Shirogane plot with the bamboo next to it, which is my FC's house. I think it's 16/46. I've heard that a lot of players prefer the two other large ones though.
Our plot doesn't have a hotspring next to it, but it has the bamboo and this beautiful large pine tree on the mountain behind it, and behind that is a bay that you can see when you climb up the roof. We pretend that's where our submarines can come out. ;D
The only downside is that we are in the subdivision where the house is facing the northwest side. The sunsets are pretty, but I'm more of a south side type actually (even though I can't be in the sun for long irl).

I also really like Lavender Beds plot 11 (medium), even though I never had it.
I have plot 30 as my private house there and my boyfriend has the small one directly across of it. I would never have taken it alone though, because I don't like having a neighbor directly across. Together it is great though. It's close to the really huge tree, so pretty when the light shines through the leaves on the way between the houses.

Both plots don't have a market board or aetheryte directly next to it, but I don't mind that at all actually.