I have to go back to Professor Breyer on this. These things rarely were made up completely out of whole cloth, and there is at least a plausible case for an exodus which was a. much, much smaller than the one mentioned in the Bible but still extant, b. not associated with nearly all of those plagues, which, even if you did believe in higher powers just seems like overkill to me, and c. pretty well exaggerated in other places as well ( for example, no way did peeps wander around for a full 40 years before discovering Canaan unless said wandering is code for "led a purposefully nomadic existence", which itself is a bit contradictory to Moses' stated intentions).
That being said, it's not completely out of the ordinary for something like what this would be - a small scale slave revolt in the Nile delta area which was aided by some lucky weather - to be ignored in the Egyptian annals. There are several battles with the Assyrians which the Egyptians lost, for instance, that aren't recorded in Egyptian history much at all but were pretty well documented by the other party. Egypt, or maybe what I should say is "what we have left of Egypt", had a really bad habit of passing over the bad parts in favor of the good. Given that most of what we have left are inscriptions on monuments and etchings in the graves of pharaohs this isn't so unreasonable (compare and contrast with the Greeks and Romans, from whom we have lots and lots of written documentation and histories... if all we had of the Roman Empire were Trajan's Column and the various buildings of the emperors, we wouldn't know much of anything about Teutoburg Forest or Cannae or any number of major Roman defeats).
In a perfect world you'd be able to say that the Jewish exodus is an extraordinary claim which requires extraordinary proof. History, particularly lightly documented ancient history, isn't so clean-cut so as to easily differentiate exaggeration from outright falsehood though. Treating the Old Testament as a historical document with the same amount of accuracy as, I don't know, the chronicles of Gilgamesh or whatever, I don't think you can necessarily emerge from it thinking "oh, this is obviously a whole bunch of their version of fantasy literature".
