Well, I would certainly recommend starting with 4x5 before you move up to 8x10. It's a much easier and cheaper way (in terms of camera, lens, and film costs) to learn how to operate a large format camera well.
Large format cameras are great for landscapes because of their enormous field of view. However, wide angle lenses can be very expensive (look up the 58mm or 65mm Schneider Super Angulon and you'll see what I mean). They're particularly well suited to architectural work because the movements (rise/fall, tilt, swing) allow to you correct for perspective distortion when shooting wide. They're also helpful when shooting, say, a very tall building, to correct the appearance of the building getting skinnier at the top that you'd see in a small format lens.
They can also be tons of fun with portraiture. The negs are breathtakingly detailed (though this will show every skin imperfection). And using movements you can selectively focus on certain areas in the field of view. For example you could have one eye in focus and the other out (dunno why you'd want to do that, though).
However, they do often require you to stop down more than small format lenses. Many LF lenses will stop down to f64, a number of them will stop down even further in 8x10 and larger. As such, you're losing a bit of light.
There are two kinds of LF cameras: field cameras and monorail cameras. Field cameras are generally lighter weight and fold up, so they're much easier to cart around in "the field." However, their movements are often limited compared to monorails, especially on the rear standard (google that term). Monorails are traditionally studio cameras, because they are metal-bodied, generally heavy, and always shot on a tripod (as opposed to some field view cameras that can be hand held, like the graflex speed graphic). I shoot with a 4x5 monorail and love it.
In terms of lenses, your standard lens focal length is generally 135mm or 150mm. Anything 90mm or smaller is wide angle. Portrait lenses start at 210mm generally.
I'd buy a cheap metal-body monorail to start. The first three lenses I would buy would be a 135mm Schneider Symmar, a 210mm Caltar, and a 90mm Super Angulon (the 90mm isn't nearly as expensive as the super wide angle Super's).
Hope that helps.
--Max
. Oops I meant foldable view cameras. 
