As an avid storm chaser for the last 4 years, I'll throw in my two cents.
CF definitely conducts far less than aluminum. That's cool that Ben broke out his multimeter and tested the resistance. (Thanks Ben!) So on a micro scale level, a CF will keep you safer to some degree. However, I say on a micro scale, because there's a lot more at play than just a 60-inch tripod when lightening decides to strike.
There are some things you can do to help protect yourself when shooting lightening in the field.
When shooting lightening when it's really close (a couple of miles), I do one of two things. I either set-up my tripod just outside of my car and use a lightening trigger or I'll use a bean bag on my half rolled down window. The key here is that I'm in my car, which provides a large degree of safety. As long as your not touching the metal parts within your car, you will be very safe if lightening hits your car. Yes, there's a very remote chance that a lightening bolt could come straight through the roof, but it's very rare for something like that to happen.
When the lightening is more distant (at least 5 miles away), I will often stand out in the field with my equipment. However, if at all possible, I will make sure that I'm lower than other objects nearby. (A slight hill, a power line pole, etc. However, keep in mind that this does not guarantee your safety. Lightening can strike up to 10-15 miles away from a supercell thunderstorm (they're called bolts from the blue), so distance does not really assure your safety.
Lightening triggers are wonderful devices because they fire your shutter when a flash occurs. Because lightening is so quick, the success rate for catching the bolt when it is really bright is nowhere near perfect...perhaps around 30-40% of the time. Another benefit is that you can try lightening photography during the day, which is nearly impossible without a lightening trigger. And perhaps most importantly, it does the work for you so you can remain sheltered in your car.
Aside from all of this, if I were you, I'd get a CF tripod. Yes, they are safer (to a degree), but CF tripods are just plain superior to aluminum tripods in every way.
You should let us help you spend your money...we can make some great recommendations when it comes to RRS and Gitzo tripods!