DAW:
Reaper. Theres really no reason whatsoever not to start with it. Its the same sort of product as the 'name' DAWs in its capabilities (they all differ slightly, but theres no more difference between, say, reaper and cubase than cubase and protools, and theres no 'winner' there either; its all preference and what you specifically need from it at the end of the day)
However, DAWs all have the same basic core capabilities. They implement them in slightly different ways, but your first priority is learning things like bussing, sends and receives, automation, editing, comping, and a million other things and combinations of them. All of them do these things. Learning these core capabilities and the basics of building a mix (I jest; thats a lifetime job), but where to pan things, rules of thumb on eqing, layering, how the basic mixing tools work (EQ, compression, reverb, delay, etc etc etc) can be done in any DAW and reaper is the easiest. I also think its the best, and moved to it from sonar (which I moved to from cubase).
Interface: Stability and well written drivers are the most important thing. Equivocating about frankly small differences in conversion quality and mic pres needs to take a very distant second place to dropout-less low latency performance. I recommend focusrite saffires by default (if firewire is an option; hopefully it is, as its better for audio).
Monitors really needs to be 'monitors and room treatment'. Your room is going to be a bigger problem. Rockwool slabs, wood, screws, some fabric and some patience. A spot of open celled, dense foam doesnt go amiss either. Headphones negate the room totally, and so are always a useful compliment, but they have their own issues. The main thing on headphones and monitoring is, in order, its linear enough that there are no big nulls; frequencies you cant hear because they're too quiet compared others and are being masked, and you know them very well.
Program for guitar sounds - SM57 and some patience.