...systems in general? Turning once again to Bill Gates' comments in Newsweek magazine, "In every product we ship, the teamknows of features that I asked them to put in that they did not get in. So you never ship a perfect software product...
http://www.computerweekly.com/234239.htm
...one box, any stack will do. If you have a medium site that needs hundreds of requests per second, go with what your teamknows best. But beyond that, once you get the hundreds of thousands of queries per second, everyone builds a custom solution...
http://blog.stackoverflow.com/