Ok, now i know i am somewhat biased, but imo there is no other submarine war movie that comes even close to catch the claustrophobic feeling you get inside a sub then this one...
I got recently hold of the original 6 hour miniseries (it was screened on german and austrian TV as a six hour miniseries before the cut version came onto the big screen... Now if you dont mind subtitles (dont worry you will forget them after a couple of minutes, and a WWII movie were german soldiers are not presented as pure evil but humans like you and me) you wont get a better catch then this one. (btw. the DVD has a english version too, its ok but not as gripping imo then the original german version...)
Oh, and how about the title music, it is by now an all time classic...
in anycase, Das Boot is with Sam Peckinpah`s Cross of Iron the probably best WWII movie of all time...
cheers
viggen