Actually, Jonathan, I think most young-earthers are willing to fudge Ussher a bit. (See how the poll was worded, with a thousand years or so of grace period for the calculators.)
I think one of the more amusing types is the generally moderate religionist who claims that while the first chapter of Genesis doesn't refer to "literal, 24-hour days", it somehow consists of a schematic summation of the way God worked through the evolutionary process.
Here's what actually is said in Genesis 1-2:4a to have been the order of the days:
Day 1. Heaven, Earth, Light/Day, Darkness/Night
Day 2. A firmament to keep heaven from flooding earth
Day 3. Dry land, Seas, Plants of all kinds
Day 4. Sun, moon, stars, diurnal cycle
Day 5. Aquatic animal life (from protozoa to whales)
Day 6. Terrestrial animal life; male and female humankind.
Day 7. Repose
With all due respect, that is neither the order described (according to the young-earthers, described in more detail) in Gen. 2:4b ff. nor in any sort of accord with evolutionary scientific teaching. The idea that dry land, seas and plants precede sun and moon in the order of creation is just weird, and the idea that whales preceded land mammalia is almost as odd.
Haruo