I'm not sure if I have mentioned this before, but I use manual focus during the majority of my shoots because I know that I can do a better job placing the focus than the camera when shooting landscapes and portraits. The only situations in which I use my cameras autofocus is for quickly moving subjects: sports, wildlife, candid, and maybe during events.
I cannot come up with one good reason why I should shoot a landscape image on autofocus--if your subject is stationary it is not difficult to use your view finder or the circle of confusion to completely nail the focus 100% of the time. You can even use both to double check your focus. If you're using a zoom lens, another technique you can use is the compose/zoom in/zoom out technique that allows you do zoom in on your subject to check your focus.
Another tool that I use is a hyper focal distance calculator on my iPhone or iPad. With this tool you input your camera sensor info, focal length, aperture, and focus distance, and the calculator will tell provide you with how much depth of field you will have in focus. From using this tool frequently, I can guestimate how much DOF I have with certain focal length and aperture settings pretty freaking accurately.
The point I'm trying to get across is that most situations do not require super-fast, super accurate, super expensive autofocusing systems. Do I love my SSM on my 70-200? No doubt; but mostly because I use that lens in situations that require focusing faster than your average landscape scene. So many intermediate level photographers I know brag about how fast their autofocussing is or how their new camera has 110 autofocussing points; which is great if they are shooting their kids soccer game, but totally useless for shooting landscapes.
And yet again, here is another blog post that has broken down to the lesson of: know what your needs are before spending a ton of money for features that you don't need. And oh yeah, try using manual focus for your landscape images :)