I use Control as well, and it was an adaptation to prevent typing spaces or letters into the password field that I would have to delete before typing in my password. Perhaps you had a similar experience.
I use caps lock, apart from being safe it also gives a bit of feedback in the form of the light going on/off even before the conplete wakeup.
I've also discovered that capslock is a useful way of detecting (linux) kernel panics. If everything freezes, and capslock stops toggling that light, your kernel is dead.
I do the same thing. It's right on the corner. And alt frequently activates a menu.
I use control. It's neutral to password entry on Windows and Linux lock screens, and either neutral or an escape key from a VM back to the main desktop.
To wake up my computers I play "shave and a haircut, two bits" with my shift keys, alternating between them.
Careful, you might let a few shots off in Quake like that. Trigger discipline and all.