Combine the Eastern Kingdoms and Kalimdor into one list. I don't want to have to scroll through two (or in this case, four!) lists to see all the zones of a similar level. You could always label each zone with its continent, if desired.
I designed it like that at first, but then deliberately broke the old continents into North and South parts, because it helps me to have a local group to focus on and not the whole continent. The way I'd do it was for hunting rare spawns in the lower Eastern Kingdoms, I'd start in Stormwind, then taxi to Booty Bay to check if it's raining on Jageuro island for baby apes, then taxi to Nethergarde to check on Scorplings (finally got one... but it's green), stop by Karazhan to fight the tamer, then fly to Darkshire and taxi to Iron Summit and look for a blue molten hatchling... and just work my way up the continent's zones to the natural division between Wetlands and Arathi. Kalimdor wasn't so obviously divided so I just picked Mulgore as central and went across from there.
I hunt in regions (like Outlands/Northrend, etc), and dividing the classic continents geographically like that helps me to quickly check for the rare spawns in a region in what seems to me to be an efficient manner.
It wouldn't take too long to cut and paste them back into an intergrated continent order, low to high as I originally had it.
This works for me, copy it into your favorite text editor and rearrange it how you like.