One of the most interesting points of contention in the evolution/creation controversy is the "speed of evolution" (or more precisely, the rate of speciation - the time required for one species of animals to become two).
Creationists actually have the more stringent requirement.
For us to observe all the species we have today, starting from the limited "kinds" taken on the ark - speciation must happen pretty quickly (relative to "geological" time scales).
Of course, the evolutionist gets hit coming and going on this one. If evolution is fast, then we should be able to observe transmutation of species (cats becoming dogs) - which we don't. If evolution is slow, then we should not even observe speciation (wolves becoming chihuahua and St. Bernards - not quite different species, but close).
Observations repeatedly show that speciation can happen quickly (latest from Science Daily).