And to shed a little light on why I think there are different levels to lucidity, just so you can kinda see where I'm coming from:

Think of lucidity in the exact mirror-image of waking life.
When you are awake, you can be so tired, or heavily sedated, you don't pay attention to anything. You're just kind of...there..zombielike. Just 'not yourself,' or lethargic, or however you wanna call it. To the extreme of this, you can be completely ALIVE with energy while awake. (usually after high activity.) There is a difference. When you are ALIVE, your senses sharpen. Your mind speeds up. You become more conscious of anything and everything around you. (Or whatever you're focusing on in particular at that moment.) Your vibratory state and sheer existence seems to transform into something completely more In-Tune, if you will.
Lucidity is the same way. If you're wandering the hallway of a dream, and you look down and notice your feet are stepping further and further from the ground with each step you take, and you think. "Hmm..wow...I'm dreaming." You're lucid. No questions asked. You are conscious enough to recognize this to not be the waking world. Compare this to being lethargic, or tired, or just 'out of it' while you're awake. Your thought pattern is "yeah..hmm..well I'm here, I'm alive (or I'm dreaming)..but so what?" That is both the lowest level of dreaming lucidity or waking Awareness. Stay with me here...I've been cheifing like a Navajo Indian,, but I know where I'm goin with this... 8)
The more you become aware of your control over your dream, the more lucid you become. The more conscious you are that everything you see (even the things in your peripheral vision that you're hardly even Noticing) is a dream, the more Lucid you're becoming. I think this also explains the "heightened senses" you get when you lucid dreaming vividly. (Many people experience this. Don't you?) The grass becomes clearer, sounds become louder, and you can Feel your dream body like the waking world.
If you pick up a dream rock while just "kind of lucid," your frame of mind could be "Hmm..if I'm dreaming, I wonder if I can make this rock into something else." You may try and try and try, and fail, or try twice and succeed. That is not what's important though...
In a High level of lucidity, you would know that Everything around you was a product of your mind, and could be manipulated as if it were a part of your own body. You would have no troubles doing what you wanted to do. (Which some lucid dreamers Do have.) There would be no questions to ask because you know that Anything you wanted to happen could, and would only happen because you tell it. Every molecule of your dreamworld would be an extention of your own conscious thought, and would be controllable by you without a doubt. (I don't even think I've had this. I'm still in the exploratory phase of lucid dreaming. I don't think anyone knows Everything that is possible in LD'ing.)
Your level of lucidity parallels your level of waking awareness. Both of them can fluctuate, (sp?) it just depends on how Conscious you are of everything around you.