Always fun to share a favorite group with someone. When you mentioned you liked the piano type beat I figured you'd like Atmosphere stuff. Atmosphere are local heroes, and my favorite hip-hop group by far. You'd probably also like "The Waitress" off of When Life Gives You Lemons, "Became" off of The Family Sign, and Pour Me Another and Get Fly off of Can't Imagine How Much Fun We're having.

All of those have a heavy piano to their beats. Ant is a big fan of the "dirty piano" sound, and you'll find it on lots of their tracks. It's why they are easily my favorite group, as I play piano, and love it when it's mixed with a hip-hop track.

If you're the type of person that likes supporting artists on small labels, here is where you can buy their music directly. If you buy from their "Fifth Element" store they get all the profits. They also have a brick & mortar store by the same name in Minneapolis where they sell all their shit. They don't mind pirates, but they try to make it easy for people to get their music (DRM-Free) through their storefronts. They also release a free album almost every year, which you can get there, and they are just as good as their studio albums (sometimes better).

http://fifthelementonline.com/collections/rhymesayers

Cheers, hope you enjoy them! :)