Slate did a nice job investigating some plot holes in Memento-- don't peek if you haven't seen the movie yet (though I imagine most Ishbadiddlers have by now):
http://slate.msn.com/culturebox/entries/01-06-27_111073.asp
While the short article does call director Christopher Nolan on the carpet for several inconsistencies, the author patiently tries to offer plausible explanations, however farfetched. In any case, the article actually, oddly, ends up *enriching* one's appreciation for the movie somewhat. The fact that Nolan came up with a plot that tracks as well as it (mostly) does remains in itself an accomplishment.