Why do I have a really hard time believing "shadowsaiyan17" is a blackbelt in ninjitsu? Well whatever. . .
You can look all over the net for info on what "ninjas really are," the unfortunate thing is that the majority of sources are mistaken or misinformed. Hell, I might be, but this is what I remember from sources that were pretty well-informed...
1.) The majority of ninja did not wear the black pajama gear. In Japanese plays, the stage-hand type people often dawned themselves in black, and as ninja became characters in those plays they often depicted them in such a way.
2.) Ninja hand symbols. This myth came from a time when a famous ninja clan was living in an isolated mountain area. In the area was also a monastery. The monks there (who did use hand symbols; but for prayer) were often confused by the people as connected to ninja or being ninja.
3.) Ninja's were not quite teh l33t assassins. There were very few actual assassinations pulled off by ninja, if any. Their main purpose was intelligence (i.e scouting), or sabotage, such as sneaking into a castle and lighting fires.
Regarding this "Who would win a fight" stuff, it's entirely situational. Ninja are in fact made for stealth; that's simple fact, if you think otherwise, you just don't know what you're talking about. There are crappy ninja, crappy samurai, and opposite ends of the spectrum for each, so you can't really accurately just pit them against each other.
A ninja would doubtful ever approach a samurai head on. Ninja-to (their swords) were crappily made weapons used for slicing throats, not dueling. More often than not they didn't even use ninja-to, because it's definitely not an easily concealed weapon, and weapons were outlawed for people other than samurai. This is how "weapons" like the kama and its variation the kusari-gama are often associated with ninja. The kama is nothing more than a farming implement, but obviously it can be used to fight (in a limited sense.) Ninjas were often if not always posing as peasantry (farmers.)
And yes, there is a reason samurai were used in wars, not Armies of Ninja like you might see in games like Tenchu. As for honor, you'll find that Bushido, much like the Knight's code of honor in Europe, wasn't the most terribly adhered to thing in the land. By that I mean there were a lot of corrupt a-hole samurai, more and more till the end of the era, I guess.
Ninjas don't need any special birthright or whatever, just training.
And yeah, I gotta say I agree to that too...
