I recently commented to a friend that reviewing restaurants is so much easier with a smart phone, taking notes on the fly and being able to instantly look up directions if you get lost on the way.

In my case, I have an iPhone, and -- sad as I know it is -- I can't imagine life before it. I'm a sick person. I know. But there it is.

There are apps that I use on a daily basis for work which have made other forms of technology obsolete. For instance, the built-in Voice Memo application on my iPhone takes the place of a much larger Ederol (which is also quite expensive). I can record interviews or press conferences, edit down the audio to its most important parts -- right on the phone! -- and email myself an MP4 file when it's done.

Likewise, if I'm dining in a restaurant and a song comes on the stereo system that I love, but either can't identify or don't want to forget, I simply use my Shazam app to identify and log the song for later access. This is helpful when every Cannibal Corpse song that Amy's Ice Cream plays starts to sound alike.

Epicurious (free)

If you've ever been at the grocery store and decided to make something on a whim, this app's for you. With more than 25,000 tested recipes in its database, Epicurious acts as both a cookbook and a shopping guide in one. Just tell it what you want to make and it'll give you a quick and easy shopping list. Also handy for last-minute dinner or party ideas.

Ratio ($4.99)

When Michael Ruhlman creates an app, you know it's going to be good. Ratio does exactly what it says: Provides a handy reference guide to the 32 "critical ratios" in cooking that Ruhlman says "form the backbone of the culinary arts." With these ratios in hand for nearly every major recipe -- pasta to bread, sauces to stocks -- cooking becomes a much more natural science, with recipes that are easier to remember and easier to build upon. It's the most expensive app of the bunch, but very well worth the price.

42 Restaurants ($1.99)

This isn't so much a necessity as it is a luxury. And at $1.99, it's a very affordable luxury at that. 42 Restaurants has compiled some of the best recipes from the best restaurants in the world: St. John in London, Nobu in NYC, Le Quartier Francais in South Africa, Vue de Monde in Melbourne...and the list goes on. Enjoy lavish photos from some of the finest restaurants you'll probably never eat at, but no matter: You can at least attempt their stunning recipes at home!

Urbanspoon (free)

Urbanspoon has an elegant solution to the dilemma of dining in unfamiliar territory. It's not Urbanspoon's kitschy slot machine-style of choosing restaurants (by choosing categories and shaking your iPhone) that I like. It's the drag-and-drop interface with Google Maps -- a recent update to the old favorite -- that has permanently endeared me to it. Simply drag the blue pushpin to where you are, and a host of great restaurants will pop up around you. Hit "list" to see their names, star ratings and more. Bonus: Urbanspoon links directly to critics' reviews of a restaurant, from Robb Walsh's to Alison Cook's, even to mine.

VegOut ($2.99)

If you're a vegetarian and you like eating out, there isn't a more useful app available than this. VegOut allows you to seek out veggie-friendly restaurants across the U.S. and read other users' recommendations and reviews. It can be frustrating trying to locate vegetarian restaurants -- and informative reviews -- on standard apps like Yelp and Urbanspoon. No more, with VegOut.

Locavore ($2.99)

Of the few "local produce" apps that are out there, Locavore is the strongest. Not only does it allow you to find farmers' markets in your area, it is a great guide to what fruits and vegetables you can generally expect to be in season. It even links to Wikipedia articles and Epicurious recipes for produce with which you may be unfamiliar. With tweaking -- better interfaces with the farmers' markets and more specialized geographic areas (by state isn't perhaps the best way of grouping growing areas/regions) -- this could be a killer app.

Simple Tip Calculator (free)

If you find that taking 10 percent of the total and doubling it -- ta-da! instant 20 percent tip -- to be too difficult for some reason, download one of the many free tip calculator apps out there. There is absolutely no reason to pay for one, however, as you could technically do this for free on your iPhone's calculator. Simple Tip Calculator is the best of the free apps, which also includes a helpful "split check" feature.

Restaurant Nutrition (free)

Dining out but still counting calories? Keeping a food diary? Simply want to know which menu items at Chili's are healthier than others? Restaurant Nutrition has nearly every chain restaurant you can imagine, along with all of their menu items' nutrition information, updated on a very consistent basis. Handy in particular for business travelers who often get stuck in small towns with few other dining options.