The student probably wanted pro advices, since she went to LL. I am talking as an amateur. In one sense, however, we are all more or less "amateurs", considering the digital revolution during the last few years. Nobody really knows if it is wise to buy gear from Canon, Nikon or some other, perhaps smaller brand in a 10-15 years perspective. We`ll all be surprised by developments in sensors, lenses, focus issues, post processing etc, since digital photography is still in its infancy.
For me money was an issue, and in October 2005 I got a Canon Digital Rebel (350D) and a Sigma 30 f/1.4 (like a "normal" 50 mm on "full frame" or film camera), and tried to learn photography with one prime lens. Six months later I got a small 24 & 50 mm (I like "street photography" and casual portraits). I didn´t regret this path. I think I learned the ABC of photography better then if I`d started with a wide zoom, a normal zoom and a tele zoom.
But if money wasn´t an issue, and I should buy a camera today, focusing on "landscape, action and portraits" (as the student says), this is what I would do:
I would get a Canon 5D (full frame for landscape), buy a 35 mm f/1.4 and focus on landscape for 4-6 months, learning to see with a moderate wide angle lens, learning the elementary but important secrets of depth of field/bokeh, and really get familiar with the perspective from this lens.
Then I would get a 85mm f/1,8 or 1,2 (money no issue?), try to learn portrait photography (and more about bokeh) and try to shoot some indoor and outdoor action with it.
Then, after 8-12 months, I would buy a 200 mm (or 300 mm) to learn the perspective of a tele lens (and for action/sport & landscape, birds, wildlife etc).
And then, if I was curious (and I probably would be very curious!), I would get a zoom lens, to see if it was of any advantage to me.
To make it really simple, I would consider using only ONE LENS FOR ONE YEAR, say a 50 mm f/1.4 or 1.2 (on the same Canon 5D) instead of the three mentioned above. But with those three lenses I imagine I could take most of the pictures worth taking, and learn most of the ways of seeing, in photography terms, worth learning.
If, however, weather sealing was an important issue, I would go for the high end Nikon, or Pentax K10D (perhaps not Canon right now, since they probably will come up with a new one quite soon), and lenses equivalent of moderate wide angle, moderate tele, and a more far reaching tele.
And if weather sealing and full frame wasn`t so important, but size was, I would go with anything smaller, from Canon or Nikon or Pentax, or the recently announced Olympus cameras. They all have excellent lenses, some stronger on the tele side (Canon), some better on wide angle (Nikon? Olympus? Pentax?), some more compact (Pentax) etc.
I think the biggest danger for someone with money to spend on gear, is to get too much too fast, and never really learning how to use it.
In any case, the "student" starting this thread (is she really a student, or just someone who wanted to see if she could trigger a fight at LL with her title "Nikon vs. Canon?"??) have got too many advices – and here I offer my two cents...!
But this thread is probably read by a few former film photographers who wants to buy his or her first DSLR, as well as people starting with a digital camera without former experience with film cameras. My advise for the latter is a camera that fits the bill and the purpose of your needs, and ONE to THREE prime lenses.
It could be a Pentax, or perhaps a Panasonic.
(Or should I go for a Sony, since MY sister says that Sony is THE INDUSTRY STANDARD?)
Paul