Canon's are always in style and never loose value. I have an AE1, I used in my job in the Army and still use. I have the Rebel T1, the OES D50, A few ggod lens, filters, and I am good to go. Buy the body and good lenses (not kit) You can always use it. I will get another digital in about 3 yrs. Am getting llights, other support equipment, studio, etc stuff. Buidl your equipment slowly. Invest in good lenses. They will change..AE1 has bayonet mounts.
Some believe it may be two years down the road (the next 7D). I agree with bouchandre -- buy what you need now without worrying about what's next. If you need it, you need it.
I don't really think that we will see a 7d mark II anytime soon, but rather a 5d mark III. I got the 7d a couple months ago and Ilove it. Although I would really like to have the full frame sensor, I had to go with my budget.