SOBA (そば) is a noodle made from buckwheat (蕎麦). It is definitely unlike other noodles made from wheat such as udon. Soba noodles are also better if you're counting calories. One cup of buckwheat soba noodles has about 110 calories. Pasta made from wheat has about 220 cal per cup.
Whole wheat noodles fall somewhere in between with about 175 cal/cup. A very popular dish, yakisoba doesn't use real soba noodles. While the word yakisoba literally means "fried soba" (焼きそば) the noodles in yakisoba generally are made from wheat flour. If you're like me, I tend to go for whatever tastes the best at the time!