This is a common fallacy. As manaheim noted -- it's back. It's the "I shoot manual cause I'm creative" zombie that can't be killed. So here I go trying to pound another nail into the coffin fully aware that it will rise yet again.
Manual mode can be necessary when using external flash and or an external meter. I wouldn't own a camera that doesn't have it. If you prefer to use it out of habit or whatever fine -- float your boat.
BUT manual mode does not provide additional creative control over using a camera's semi-auto S or A modes. In fact it's most likely the opposite because the odds are very high that you're less efficient using the camera in M and that efficiency loss can inhibit creativity.
Take your landscape as an example. I put my camera in A mode and set f/11 for my aperture. You put your camera in M and set f/11 for your aperture. We're equally creative at this point. You watch the meter in your camera and select a shutter speed that zeroes the meter. I let the camera do that for me more efficiently and note the selection. (I have the slight edge now as I'm faster).
You decide to get creative and manually shift the shutter speed to increase exposure because you know better than the camera meter -- very creative. I also know better than the camera meter and I shift the exposure the same amount using the exp. comp. control of my camera -- same result; I'm just as creative and you're just slower.
Joe