Both companies are guilty of making death meaningless. DC had Batman "die" last year where he actually just got sent back in time. Marvel, as Bab mentioned, killed off Cap, Human Torch, Ultimate Spidey, and Nightcrawler recently. Most of which were spoiled by releasing that info to the news organizations before the comics came out, pretty much ruining any emotional impact the reader might have had.
Cap is back, Nightcrawler is from an alternative universe (oh noes!), and Human Torch is returning soon. The Ultimate Universe is pretty good at keeping people dead for the most part. They actually create legacy characters in much the same way DC does.
Also the Multiverse ceased to exist from 1985 to 2005. And now it seems like they got rid of it again with the reboot. Well, except for the JSA who are WWII heroes. Believe that will be separate.
EDIT: I reviewed O.M.A.C. #1 for NOTR:
http://nerdsontherocks.com/review-shooter-o-m-a-c-1