The only issue I can see with trying to learn from paintings by the old masters is the issue of style. A lot of the interest in the shot comes not from what the painting is of but how it was painted, whether it be the type of paint or canvas, the realsim or lack of it or the colours used. With photography you don't have that degree of freedom, you do have various processing options such as black and white, cross processing, HDR, etc. but the photo will still be realistic to what is actually there. There is definatley something to be learned but its not as simple as recreating a particular painting.
Give it a go though. No harm in trying and with digital its free. People well placed can really enhnace a landscape. The photo of mine you commented on, on flickr, is one of my favourite landscape shots where the people feature very prominently and without them it wouldn't work as well.
