Alright Johan.
I spent a long time cycling through that part of the world so do know a fair bit.
I was there a few years ago now so prices may (probably) gone up. at the time i was there it was good value and cheap but they were still recoivering from the crash. But i reckon if you are careful 10-15 dollars aday should do it.
Buses are great value as they cover such a big distance so if you are backpackibng you can get around cheaply, accomodation is also cheap (it was about 4-7 dollars for a bed in an hostel) steak is cheap and supposed to be the best in the world ( i am a veggie) but on the whole food is better than in most of S am where it is bland per se.
They are big on camping, most cities have a municipal campsite which is normally very good esp Salta****, mendoza *** but everywhere that is worth seeing will have camping options.
It is safe on the whole usual precautions!! dont be foolish and you wont get fooled but in the cities there are dodgey folk as always.
As far as best destinations
El calafate...perino moreto glacier...but windy!!
Igauazu falls
to be honest i would struggle for a third...people rave about BA but to me its just another city as they do about mendoza but for me the best thing was its proximity to aconoagua (highest peak outside of himalayas) with its good trekking options.
Torres del paine is actually in chile, but is great i think the above may have confused it with fitzroy, which now i think about it would my top attraction in arg. 9cant remember the name of the park.
Chile is loads better, carretera austral, pucon, patagonia, atacama and people. also bear in mind that the distances are massive and alot of the land is crap and boring by comparison to chile.
1 year is along time in my opinion to spend in argentina, i would say head to chile, peru and bolivia and do a month in argentina.
If you freind request me on facebook (rich pain) you can look at some of the pics i took to get a better feel of what i mean.
Hope this helps
Rich