BCpoweder - really sorry to hear about the injury!
I feel your pain, literally. I tore my right ACL on the 1 year, to the day, anniversary of my left tear. My left (2009) was pretty bad. Swelled on the spot, instantly unusable and meniscus tear in two places. I had it repaired within 3 weeks of the injury. I wasn't even sure I had torn the right until well after ski season. It wasn't unstable under flexion. During recovery for the 2nd ACL, I re-tore the meniscus in the left. I've yet to get it scoped. After some cortisone injections, its actually been relatively pain free….mostly… sorta.
The good news is that I had an awesome (although thanks to recovery time, an abbreviated) season this year. Both knees did fine, even the one with the currently torn meniscus.
Before I get into what I've learned - here's the good news: you can be as active as you want depending on treatment. If you want to ski, hike, run, etc then my non-clinical opinion is that should be a very reasonable goal.
Worth stressing again, I am not a physician, although I work closely with many professionally - my opinion is based solely on my experience and what I've read and learned.
last year there was an interesting European study that found rehab to be as effective, in the long run, for ACL tears as surgical treatment; with one caveat: the patient had no stability issues. The college of orthopedic surgeons still recommends surgical repair for instability issues for anyone who wants to resume normal activities (consult your physician, your milage may vary). I've not regretted either surgical repair. I will candidly say the post surgical pain and recovery is manageable but the rehab stinks - mostly from a time perspective. 3 days a week, a few hours each time for up to 3 months… its a lot to commit to and it is a commitment you have to make.
The second time around (2010), I knew what to expect which made it both easier and harder. It was easier in terms of pain management and expectations. It was harder in terms of the time. I had the advantage of some stability - enough that I was in the gym for 3 months before survey (and diagnosis). I really worked my quads hard (b/c I was gearing up for the season) and it paid off. My rehab time was much shorter. So if you doctor ok's it, you might work on some quad, hamstring and hip strength before you have surgery, if you decide to have it.
Finally, everything I've heard and read is that there is not really such thing as a partial tear. The ligament pretty much disintegrates upon injury. Again, I'm no doc, I've seen plenty of ACL MRI scans and have been told that partial tears are a misnomer - its more like my 2nd injury where its totally gone but the swelling and gross instability are not as pronounced. Again, your experience could be different.
I guess my best bit of advice would be to research as much as you can. Get as many facts and ask as many questions as you need to feel sure that the decision you make is the right one. While surgeries were the right choices for me, you have nothing to lose by trying rehab and PT - if the instability doesn't improve, you know what the next move is.
Good luck - speedy recovery!