A couple that you mentioned, SK, don't interfere with each other at Marvel, either. The "Ultimate" universe is completely separate from the 616 (regular) one. The only big crossover right now is Dark Reign, which stems directly out of the recently-ended Secret Invasion (which tailed on World War Hulk, which was born out of the Civil War which was spawned by the House of M which wouldn't have occurred without the 2nd Secret War - copy?).
Never mind. Marvel does have too many big mega crossovers. :head spinning: