4 Legs or Eight?

I have always been intregued by the notion that a spiderbot should have the number of legs in real life. According to the wikipedia entry at http://en.wikipedia.org/wiki/Spider, spiders have eight legs. That is probably because of the environment that they move in requires a little more dexterity and having eight legs gives them the dexterity for the task. However, since more legs will cost more money, I am willing to compromise on the leg thing. I am going to go with six legs primarily because it provides a stable platform for walking and most spiderbots that I have seen on the internet have six. This also leads to an interesting way of movement. The cockroach has six legs and moves with a combination of three legs on the ground at any one moment, giving it a very stable platform. The cockroach movement is actually two on one side with a third leg on the opposite side on the ground while the remaining legs move. It also gives the cockroach the ability to move quickly and turn quickly, something that I would like to try out. However, I am still going to refer to Bob as a SpiderBot, not a RoachBot.