Ok, watched both of these the other night ...
"Dawn of the Dead" was a bit comic while trying to be scary IMO (very predictable), Shaun of the Dead was genuinely funny and not a bad scary flic in spit of that.
What was your favourite?
I think "Night of the Living Dead" was scarier that DotD because it was grittier. Horror films are better low budget (ala Blair Witch).
"28 Days Later" was scarier because it looked more realistic and was gritty instead of glossy.