The word "direct" carries with it the thought of someone giving directions, which means that, more than likely, that person will not be accompanying you on the journey. You are given directions to follow, and it depends on how well you follow those directions (or how well the person was at giving directions) as to whether or not you'll arrive at your destination.
The word "guide" carries with it the thought of a companion who knows the territory and can help you find the path for which you are looking.
While it is true that God does direct and guide us, my favorite part is that He also leads us. The word "lead" carries with it the idea that someone is walking ahead of you, clearing the path, removing the obstacles and keeping a lookout for impending danger. When someone "takes the lead", he/she becomes the navigator and the one to test the trail ahead.
I prefer for Jason to take the lead when we go hiking. For starters, he knows where he's going. But also, he clears the path for me. He watches for snakes and other creepy-crawlers that might give me a fright. He also walks through all the spider webs so that I don't have to. Yes, I like it when he takes the lead.
But how much more is it a comfort to know that God leads me! He doesn't just direct me by telling me which way to go. He doesn't just guide me by walking alongside me. But he leads me. He goes before me. He clears the way. He prepares the path for my arrival while simultaneously preparing me for the path. I have no reason to fear the trail ahead because I know that He's already been there.
David understood this truth when he wrote the 23rd Psalm. "He leadeth me beside the still waters. He leadeth me in the paths of righteousness." And because David knew he was being led, he could say with confidence, "I will fear no evil."
I'm so thankful that the Lord directs and guides me as I travel down life's road, but I cannot tell you the joy that I feel from knowing that He leads me as well. I know I'm in good hands. Even if I am a bit navigationally-challenged.