Its really not as sensational as claimed by apologists. Floods being a common occurrance, especially near river deltas and fertile valleys where most ancient cities developed, naturally found there way in to legend and myth. However it is simply not true that Flood stories are universal. The supposed uncanny similarities between legends is often the result of exaggeration, or in some cases where the similarities are real, the result of Christian missionary activity or quite simply logical narrative plot details (like using a boat to escape). As was already said the Near Eastern cultures did have a direct cultural and linguistic relationship and it is not therefore surprizing that, say the Summerian legends and Babylonian ones for example,their stories have similarities.
If someone presents a list of flood lengends, ask them if they know the complete stories so as to know if the similarities are being exaggerated and when these versions of the legends were written. Its these details that debunk the alledged uncanniness.