Thought I'd start a thread for discussing plants that are particularly good around the pool and plants that are particularly bad. Obviously there's going to be some differences based on climate.
On the good side, Pin Oak trees are pretty good as far as trees go. The reason is that they tend to hold onto their leaves far later in the year than most pools are open. Sometimes they keep most of them through the winter, but they always drop them when the cover is on for me, which gives them a in my book.
Elephant Ear, which is Caladium or the other related plants known as Elephant Ears. These are a good tropical-looking plant for pool landscaping. Bulbs have to be dug for the winter, though.
Banana Trees are another good one for tropical ambiance. They also have to winter indoors except in really warm climates.
On the bad side, Crape Myrtles (the correct spelling, by the way). Those of you not in the South may not realize that they grow as a shrub that flowers most of the summer in freezing climates, but they drop all kinds of stuff on the ground. Fine for general landscaping, but not near a pool.
Morning Glories and Hibiscus need some space between themselves and the pool due to the mess they make when they drop blooms.