you get to keep your 17-85, you get a little bit more reach with that (24-105 equivalent). So then you get all the nice things like focus, and af for things like the oars and cat you shot. I'm sorry to say that you don't have the gear to move up to ff, and other than portraits, it may not benefit you.
Moving up on cameras is all about what you shoot, if you work well on crop, than keep it, if your hindered by it, go to ff. the 5d ii is descent, so don't worry even if you buy one, I shoot with a rebel and I've used the 5dii before. They both have 9af points, and the 5d ii actually has 1+ fps! So if you don't do that much action, get the 5d ii, you'd just have to sell your 17-85, and buy a sigma 24-70, which is decent for the price or the tamron 28-75, both are decently priced used. Sigma for the compactness, or the tamron for the sharpness.
But it really is up to you, if you feel comfortable, with what you use, and all you want is better iso! The 7d would work better, without you having to learn how to go about using ff. but if you like learning, and you about photography in a lazy faire fashion, then get the 5d ii and a new lens, it would work nice for what your doing as an enthusiast, that is what the 6d is designed for, while the 7d is the pro-flagship aps-c body for action and wildlife shooters.
So really the 5d would work for you, you just have to fork in a bit more $$$.
But thats only when it comes to the two.
I'd honestly suggest a 60d/50d, the get better ISo, have better fps, and the 60d has video. The low price could give you some money to put towards a 70-200 f4 (great iq) and a 17-40, with you 50 filling the gap, at that point ff, would be good. Because right now, your used to the crop dslrs, and you should just ease into it, jumping into it can screw you sometimes.