There's the obvious issue of bringing an expensive piece of electronics into the kitchen—many people already bring their laptop in, and know the perils of spilling flour into the keyboard or splattering vinaigrette onto the screen mid-emulsion. The iPad has a mostly solid-body construction, which means no food stuck between the keys, and also takes up a lot less space than a laptop, which is good for city apartment kitchens with limited counter space. Lying it flat on the table would be hard to work from, so you'll want a good stand, as well as a screen protector, like the one Zagg makes.
A few of the best stands so far are:
1) Scosche Kickback Case, who also make a successful iPhone stand.
2) iCarry by Ozaki, which is a carrying case and stand in one.
3) BookArc, which can rest the iPad both horizontally and vertically (pictured at right).
Turning to the recipe apps, pickings aren't that robust yet. But the developers are no doubt cracking the whip as you read this. Some of the most notable ones already out are Epicurious's free app, which is basically an updated version of its iPhone version to look and feel more like a cookbook, and Big Oven's 170,000-recipe-strong app, with grocery list functionality and an intuitive interface. It's free, but will cost you five bucks to get all the bells and whistles (video demo below).
SousChef's $7.99 app includes over 150,000 recipes and "step by step directions [that] let you keep your place so you can focus on cooking," whatever that means. For utility, the $3.99 Smart Chef Suite converts between standard and metric measurements, and provides a food dictionary and substitution info.
Then there are the assorted niche apps that give you stuff like 50 Italian cooking recipes or 100 vegetarian recipes. But the problem is that none of the apps will play nice with each other. Ideally, you should be able to save recipes from different apps and publications and have them all bundled into one master cookbook—which truly would be a cookbook killer.