You could work around this using any number of utilities (most of which were designed primarily to restore the missing Start button, essential if you are working in Desktop), but with the release of Windows 8.1, Microsoft has added the capability.
In other words, now you can boot directly to the desktop. It's not immediately obvious how--Microsoft still doesn't outfit Windows with any "guides to new features" or the like, a silly oversight--but at least it's easy once you know the steps.
1. After booting Windows 8.1 (here's how to get the preview if you don't already have it), click the Desktop tile to enter Desktop mode.
2. Right-click any open area in the taskbar, then click Properties.
3. Click the Navigation tab, then check the box next to Go to the desktop instead of Start when I sign in.
4. Click OK, then reboot. Windows should plunk you right into Desktop.
And that's all there is to it. If you want to go back to Start-screen booting, just repeat the process and uncheck the box in step 3. (Also, if you don't have a Navigation tab, leave a comment letting me know. This appears to be an issue for some users. I'm investigating why.)
What are your thoughts on this? Where do you prefer to land when you boot Windows 8?