Hey Justin!
As a fellow Canuck in his early 20's - Great idea to get out before the winter really hits or before age hits you!!

Im 'stuck' working in Northen Alberta right now, saving up my travel funds, and let me tell you, it isn't pleasant with winter already here lol. One more Canadian winter and Ill be on my journey as well!

I have definitly had a lot of time to plan/daydream/research and the sorts so I wanted to give you some of the advice/info that I have been able to dig up.
One of my friends up here recently did 3 months backpacking through SA and he gave me some great advice. He actually did the hike up to Macchu Picchu on the tracks and said it was an amazing experience (as this is one of my plans thanks to the fantastical Greg!), Although his word of advice was to check the local conditions as a mudslide recently shut down the track and it is fairly prone to such, so make sure to be safe and do your research on the weather conditions.
Also, If your into street art or the sort - Sao Paolo has one of the most vibrant scenes in these terms, on houses, alleys, garages, businesses, and even a gallery dedicated to the art form. I had the pleasure of viewing hundreds of my friends pictures and...sigh i wish it was summer 2011 already!! Where's that darn time machine invented from the future that came back to the past!

Where as here in NA we loook down upon grafitti, in SA it is veiwed as a true expression of their culture. Definitly something I am looking forward to experiencing.
Brazil is definitly the more expensive of the SA countries where as bolivia will be one of the cheapest and will stretch your budget even further if you linger there or say peru or ecuador.
www.oneyearoff.net has some great info on there for SA.
As for learning spanish i would type in "country of choice" + spanish schools into google and there should be a good amount of information and websites on there for you. I did this for guatemala as this is going to be my first destination i will be at for 30-60 days, and I was looking at a number of schools between 150-200 USD / week, and this includes room and board with a local family

+ activities (salsa, arts, etc and weekend excursions). This is what I'll be doing for the first 3 weeks of my journey to get acclimatized, make communication far more comfortable, and to be able to get the immersion I want. My advice would be to attend spanish school in a cheaper country if it's something that would be of interest to you.
Also, great way to reduce your costs even more, couchsurfing.org

from what Ive heard it is a great way to immerse yourself in a culture and get straight-hand experiences from the locals.
Im so excited for you, for your adventure, and your decision to travel!! Who knows... if you go for it longer term then maybe we'll cross paths in the future!
Hope any of this info can help you out.
Have a great adventure and happy - no no superfantastictremendesplendifical - travels to you! (figured given the proximity of the date when your leaving it deserved an even better made up word lol)
-Jon-
P.S. Ill have to post some pictures in Jan from my trip to Arizona to visit my parents. first time to the US of A as an adult and im really looking forward to the desert! should be a nice pre-cursor to my journey, as my parents are somewhat gypsies living in a motorhome year round

like father/mother like son lol! Any advice on any of the must-see, less heard of, sites in AZ?