I've heard lots of talk abou Sennheisers, but what about AKG headphones?
Are they good for use with a DP?
For instance the K240 MKII, or the K 141 HD or K 242HD?

The K240 is my all time favorite. It has beed the standard headphone for recording engineers for decades. The new version is better hen mine with it's replaceable cord and lower impedance.

But for practice at the piano they may or may not be ideal. I have two kids and they have a TV set and video games and these things make noise so I prefer headphones with better sound isolation. The "open" k240 has almost zero sound isolation. Recording engineers don't care about this because they work in a sound proof room.

Musicians when recording in a studio will want closed headsets so the sound in the monitor headsets don't "spill" into the mic. (Many times a musician will be playing while listening to a drum/bass mix or maybe just a click track)

Bottom line: I like the K240 because they are "dead accurate" as monitors but they may or may not work in your environment. I use a pair of closed AGKs for practice to shut out the noise even if the sound is not as good, I prefer the isolation.

Unless you are recording with an open mic the sound "spill out" from open phones is not an issue. It is a very low level