There are plenty of keyboards that can double as midi controllers. You want something with on board samples or synthesis for learning. It doesn't need speakers but it should at the very least have a headphone jack. Wouldn't worry too much about the amount of keys personally. I find bigger keyboards cumbersome to use and store, it's why I barely ever use my big synths.
88 keys is definitely a benefit and if you can get it now, I would recommend it. Though for just starting out, ya you probably won't use them for a bit, which is fair, but its still nice to have. But here's the thing the Yamaha comes with built in speakers, and is pretty much plug and play. You can use it anywhere you want as long as you have a power source. A midi controller needs to be connected to a computer, and have a program on said computer that it can control, hence the controller part. Though having it plugged into a computer though gives you an unlimited supply of different sounds you can use.
For keyboards, that is the best you could probably get, but for controllers you could also look at some alesis ones as well, but the m-audio will do just fine. For both you could also try looking at used ones as well.
If you are looking to use a keyboard, you could use stand alone programs, or you could use a daw which gives you the benefit of recording yourself so you can listen back.
If you were to use a daw, the only ones I'd recommend that are free are reaper or garage band.
I am not sure about garage band, but on reaper you can use any virtual instrument that comes in vst form.
Some virtual instruments you can use are Kontakt(can also be standalone), spitfire labs, piano one to name a few, with a bit of searching, you can find some many great ones, and find the ones that you think sound the best. You can also get many great free synthesizers
