If you've got Kontakt, at least in a Komplete bundle (I just upgraded from Komplete 12 to Komplete 13 yesterday), you've already got a number of very usable pianos. I've used The Grandeur (a Steinway, I think) more than the others, but I've also used others when I'm looking for different flavors, including The Gentleman (an upright), The Giant (a huge, and quite different, piano with sound design features), and probably others. I was just playing with Noire, which is new to me, last night. I think it's based on a Yamaha grand, and there are two models, one "pure" and one with a layer of felt added, and both versions also have sound design features. I suspect I'll end up using that a fair bit, too. I've also got Alicia's Keys, which is a Yamaha, and I've used that on some recordings.
Other pianos I've used a lot include the Galaxy Steinway (which also runs in Kontakt) and the Garritan Steinway Basic (I don't think that is available anymore, though) -- I do tend to prefer Steinways for most of my normal stuff. There is just something about the way playing translates to dynamics that I prefer (in real life, too) compared to Yamahas, where I usually feel like it's more of a loud or soft thing, but tougher to get smooth gradations in between. (My own piano is a 1940-something Story & Clark spinet, so perhaps my preference in action is based on that since I've played it nearly every day for over 55 years now -- started when I was 4 and just turned 60.) I also have the East West Boesendorfer 290, but I don't think I've ever used it on a recording to date. I've also used Arturia's Piano V2 on some recent recordings. It is physically modeled, rather than sampled, and it can emulate a number of different types of pianos (including both American and German Steinways). Guess sampled pianos for me are like the equivalent of guitars for guitarists -- you can never have enough of them.
I should note that my music tends toward pop, rock, country, etc., not classical, and only occasional hints of jazz and other styles. These days I'm playing the sampled pianos with a Roland A-88 controller.
If you do have Komplete (not sure what comes in Kontakt outside of the Komplete bundles), I recommend just trying all the pianos in that to see which ones you like for what types of music. If you have Arturia's V Collection, their Piano V2 is included in that.
Rick