Regarding headphones, take a look at the Sound on Sound shootout:
http://www.soundonsound.com/sos/jan10/a ... phones.htmI've got two pairs at the moment, BeyerDynamic DT150 and DT250. The 150s are very plain, they're hard wearing and serviceable, they've got a decent frequency response but are very flat and not really suited to meticulous listening so much as banging a track down and being able to hear what you're doing. Good isolation. The DT250 are smoother, softer on the ears, lighter, and have a more revealing sound - better for home tracking and maybe a bit of mixing. Both pairs are about £130 I think, from memory.
I used to have some 770s, but thought they were almost too flattering, and exchanged them for the others.
You can spend a lot on headphones. Get the best you can afford. Shure make some good mics but I've no idea about their headphones. They are getting good reviews though, generally speaking - not sure about that set you posted. Personally, if you can at all do so, I'd recommend going to a good shop and trying a few sets. WHen I bought the DT250s, I spent half an hour or more cycling through about six to eight sets till I decided. I had a track on repeat so I could compare how they sounded, how they felt, whether they were tiring in any way, whether they fitted my ears nicely, whether there was detail lacking or dips/humps in the spectrum that would get on my nerves or not tell me what I wanted to know.
When I'm using headphones I tend to use them through a Focusrite VRM Box:
http://www.soundonsound.com/sos/apr11/a ... vrmbox.htmFor £70 you get a good USB headphone amp, and it will allow you to select virtual environments to listen in - and they're surprisingly useful, I have about two or three regular setting I go back and forth between to help judge mixes. It's no replacement for the real thing but it's very handy.
Don't be swayed by hi-fi style talk of the kind you'll find in audiophile magazines... read a good technical magazine instead. And try some. That's the best way.
As for PT, I can't help there, but from what I see, most DAWs are pretty much capable of everything your average home recordist would want. PT is the standard in studios, Logic if you have a Mac at home, Cubase if you have a Windows machine, Reaper if you don't like the others, Live if you want performance tools. Reaper is very cheap, and gets very good reviews and seems increasingly popular - but be aware that any DAW is going to present a steep learning curve to the beginner. Take your time, read a lot, and dabble. Use whatever online tutorials you can find.
PT is not geared best for MIDI from what I understand, when compared to Cubase/Logic - but I'm repeating what I've read here, not speaking from experience, so YMMV. As for string sounds etc., you should pretty much be able to plug any USB keyboard into your machine and load up some sampled sounds and play them. That's pretty standard these days.