People joke that my yard looks like a stone yard - I have a number of different kinds of rock in different places.
I have 3/4" clean (what everyone calls "gravel" in some spots (mainly for drainage in areas you cannot see)
I have 3/8" grey pea gravel in some areas - like under the swing set.
I have 3/8" yellow pea gravel around some trees
I have what is known around here as Eastern Surnise in some areas
I have 2" egg rock around the pool.
Pea gravel gets everywhere - it is too small, in my opinion, to put around the pool. It gets knocked out of wherever you put it too easily. It works great under a swing set, because a good layer (I think I have 8") of pea gravel provides a cushioned surface for around swings and play structures.
Eastern Sunrise is pretty, it is it like volcanic rock - I really have no idea where they source this stuff from. It is unstable to walk on, and the dog hates it (it hurts his paws). It is also a pain to weed in (because it is so sharp)
Egg rock (or river rock) works great around the pool. It is large enough to stay in place, but it nests well. The rounded edges make it easy to pull any stray weeds that get into it.
3/4" clean stone is just ugly - but if you are filling in a 2' deep drainage ditch behind a shed, it is the cheapest way to go.
When buying stone, bulk is SO much cheaper than bags. If you have a need for any sort of quantity of stone, look into bulk delivery. Or, even better, if you can get it yourself, its even cheaper. Just be careful, stone is heavy. I have a small trailer. It could hold, by volume, about 2 yards of material. I will only pick up a 1/2 yard at a time (there is a place around here that will sell in 1/2 yard quantities) because it is so heavy. I picked up a full yard of 3/4" once, and the way that trailer was creaking, I was aftaid I was going to snap the axle on it.
-dave