OK I may catch heat for this but, I have personally witness two buddies go down. One at 80 one at about 65. Both wearing high quality leather jackets, High quality helmets and gloves and freakin jeans. In both cases they were completely uninjured except for a few spots of roadrash on their legs...Minor rash at that. Your results may vary widely though.
As for the Draggin jeans, my Bro wears them allmost exclusively and has had one slow speed get off that did no damage. They look comfy and have held up pretty well.
Personally I think jeans are the minimum, sorta like riding in a JR Phoenix jacket, better than a t-shirt but not something to count on if riding hard. I think leather pants and proper riding boots are probably the most neglected pieces of riding gear out there. I think we all need to probably work on that...
I would say however that Both of my buddies when they crashed would have destroyed their hands if it weren't for the good racing gloves they were wearing. The gloves in both cases looked about destroyed but protected their hands without a scratch. So my list of critical gear is as follows:
1. High Quality Helmet, Save your beans and get an Arai, Shoei, or some other High end, race proven helmet. Not the $100 special out on the sales floor, besides the good ones work better day to day... If you have a $10 head wear a $10 helmet.
2. Quality gloves, took me a couple of months after getting the Busa to finally get a pair I trust, Look for Kevlar stitching, multiple layers in critical areas like palms, and around your pinky, and a really good retention system, some way to ensure that no matter what they are not coming off without your help. Hands are full of nerves and are important tools for living, protect them...
3. Quality leather Jacket. I mean Body armor (CE approved), usually dual density with a harder outter shell. Make sure it fits kinda snug, or nothing will stay in place in a crash. Get a full perforated leather if you are in hot humid climates, my experiance they seem to work about as well as the JR Phoenix.
4. Riding boots, (I'm guilty here) but I feel boots with some kinda ankle protection would be best, I would avoid steel toes though, you want something that will absorb an impact without deforming, trapping you in your boots. I still need to find some, looking at SIDI and Alpinestar... I still wear my Corcoran Jump boots from the military...Zero padding in the ankles but a tough boot over all...
5. Finally leather riding pants, I would think armor in the knees and hips as a minimum, if you know you are not going to be draggin knees try to find some without the pucks. Again I am guilty here, though I found some really heavy Pants from JNCO that are well put together, still not much use at 150... I still don't know much about the pants, anyone know who makes good useful riding pants? Roadcrafter have anything?
OK I am done with my little Rant here, sorry folks...
Leathers don't HAFTA mean 'Leathers' per say... ya know, like there's those OTHER materials too like cordoroy or playtex or kemlawn or whatever they are that breath and are even stronger than leathers. point is, protection IS more important on a bike. I avoided leathers for a while but found a full set for $300 and decided I was worth that. 
okay, now here is another problem with finding leathers. i am 6'5 240 lbs, and although i have found a few options online that might fit, i'm sure not going to buy anything before i try it on, especially when i am going to spend close to $500. is there anywhere i can go to try these on that would have a size that fits me, or am just going to have to spend the money and hope for the best. i have also been looking for boots, and apperently they don't come in anything above a size 13, this also is a problem because i am size 14 or 50 euro, haven't found even one pair that would work in sport boots. so again, does anyone know of a place to find these, that i can go try things on? just curious
