My doubts are like this...
first buy?
> CANON 7D [1.035 eur]
> CANON EF 24-105mm f/4L IS USM (€999)
> lighting, tripods, heads...
second buy?
> CANON EF 16-35mm f/2.8L II USM (€1 250)
third buy
> CANON EF 24-70mm f/2.8L USM (€1 199)
please, which could be your opinion
Since you are just starting out and you're ultimate goal is to get the 5D Mark II (or III), then you should consider getting a cheaper body (600D) to start. Even consider a used or refurbished one, such as the 40D.
Canon Refurbished Lenses:
http://shop.usa.canon.com/webapp/wcs/stores/servlet/ProductListingViewAll_10051_10051_-1_22751
Canon Refurbished Bodies:
http://shop.usa.canon.com/webapp/wcs/stores/servlet/ProductListingViewAll_10051_10051_-1_29252
Fred Miranda Buy & Sell Forum (great place to buy used equipment):
http://www.fredmiranda.com/forum/board/10
Fred Miranda Discussion and Review Forums:
http://www.fredmiranda.com/forum/
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If you're going to be using the ultra-wide angle lens for shooting landscapes (and, therefore, don't need the extra f-stop), consider the 17-40mm f/4L, it's almost as wide and about half the cost (it also takes 77mm filters, instead of 82mm ones). Another option, is a used 16-35mm Mark I (the original used 77mm filters).
You mentioned you wanted to shoot some sports, so check out the 70-200mm f/4L, instead of the 24-105. You will double your reach and eliminate the overlap with the ultra-wide.
You could then get a 50mm f/1.4 to fill the gap in between those 2 lenses. Using a fast prime, like a 50mm 'normal' lens, is a
great way to learn exposure (much easier to blur the background) and comes in handy in low-light situations, including portraits.
(I recommend that this should be the first lens that you buy.)
In the end, no one can tell you which is the correct lens to buy. Read reviews and decide what you want to do with your camera and lens(es).
Finally, remember that a great photo depends more on the skill of the photographer, than the camera and lens. The camera
might set the exposure correctly, but it cannot choose or frame the subject.
Good luck and have fun,
DJL