I am using Piano Maestro by Joytunes. Currently for exercises and sight reading practice. I also occasionally use ForScore in place of sheet music.

Too funny, I also have a circa 75 Armstrong flute, from high school days. I had it adjusted several years ago, and then went out and bought an Azumi, based on Jen Cluff's recommendations! I kept the Armstrong, thinking I'd use it for backup when I sent my Azumi in for CLA, but I am loathe to use it, and so my Azumi has not been adjusted in way too long. I have been thinking that I should get a backup flute that I really like, so that I don't keep having this problem! At this point I'm pretty certain I'll never use the Armstrong again. Congratulations on the new flute! I know what you mean about them being like night and day from the old ones

I just started using Music Practice Assistant and love it. It helps me keep more focused on what really needs work. Music Journal, Noteflight online when I'm having problems with a rhythm and Pro Metronome. I have a real metronome and like it best.

Spotify, but more for language, though the music is cool.

Firefox to come to these awesome piano forums.

My ears are so novice that I wonder if ear training programs might give me an in, but I have not committed to that yet.

None.
I downloaded the Roland piano app when I bought my piano in November but haven't connected it to the piano yet. Don't feel the need, at least at this point.
I am fed up with everything being computerised. Too many screens. Playing piano, reading sheet music, touching paper gets me off the computer and grounds me. Gardening also grounds me, brings me back to earth literally!
Apart from the fact I have a digital piano, which is basically just a big computer, I find I am less and less on the computer now and doing more practical things including playing piano, since I got serious about piano again. I keep a spiral bound student diary for notes on daily practice.
I do have an iPad and an Android phone. The only apps I use regularly would be banking apps, Safari, TV Guide, weather and Fires Near Me (I live in a bushfire prone area and we had a shocker in my village in 2013). I don't use Facebook app any more and have got fed up with the way it is trending with its agenda so hardly go on there now. Couple of times a week for specific things maybe.
Internet is a huge time-sucker if you let it.
I felt overwhelmed just reading the list of all available apps and what people here are using.
But good luck with them and I hope you enjoy and find benefit.

I sympathize with this, but it would be a shame to throw out the baby with the bathwater. I hope and believe that it's possible to use computers productively, without getting ensnared in pointless time-wasting activities. For my part I feel no need to get involved with Facegram and Twit-time and all the other social media rubbish that youngsters ( by which I mean the under-50's ) seem to want to fill their time with.

I use two main pieces of software for music: Sibelius for composing, and Auralia for ear training. Both offer features that would be hard to provide in any way other than on a computer. I prefer to use a notebook and pencil for routine note-taking, planning, and diary activities -- at least the user interface is easy to understand.

I sit in front of a computer for most of my working day, so I certainly don't want to increase my exposure. However, if something can be done more productively using a computer, I'm all for it.