Actually the bulb for the lotus I bought a few weeks ago is the fastest growing thing in my 10g. This is a pretty low-tech, low-maintenance setup: no CO2 or undergravel-cables, 10ml Flourish Excel every other day, feed fish every other day... If you look at these two pictures, in only a few weeks the lots has sprouted a lot of leaves! This is my first tank, and my first experience of any kind with planted aquaria. I'm really amazed how this plant is growing. The only "high-tech" part of this setup is the 1x36W CF AH Supply Bright Kit.
It's sprouted even more leaves since the picture taken on 4/6. I think it will start to grow up toward the water surface soon. At least that is what the guy at the LFS explained to me, and seems to be corroborated on the web in what I can find.