The iPhone is obviously gaining popularity and market share, so my guess is at least half of the people reading this post already have an iPhone. If you have an iPhone, you know how many great apps there are out there, but it can be hard to find the great ones that you will really use. If you don’t have an iPhone, this might just give you the push you need.
Now, after having the iPhone for just four months, it’s hard to picture living without it. Below I have laid out my top apps; the ones that I would have trouble living without or that really just make my life easier. One of them is a paid app, but the rest are free.

Pandora is such a great service, and the iPhone only makes it better. You pick a song, album or artist and Pandora builds a personal radio station around it. Then just give songs thumbs-up or thumbs-down to help fine-tune your station. This free app makes it easy to listen to your music from anywhere. It even works great over the EDGE network, if 3G hasn’t come to your area yet. Now I just wish I had an auxiliary port for the stereo in my car, and then I’d be set!

RSS Feeds are very much a part of my daily life, and are the main way I get news. I really like being able to use a desktop RSS reader when I’m on my computer, but I wanted the ability to sync which feeds I have already read between devices. When I’m on my iPhone, I don’t want to have to go through hundreds of feeds that I’ve already sorted through on my computer. NetNewsWire solves the problem for me. It has created both a desktop RSS reader and a free iPhone app that both sync through Google Reader, so you have the most up-to-date listing of your feeds from anywhere. The app makes the text very easy to read, send to a friend, view in the browser or save to read later.

Dropbox is a web service that I’ve fallen in love with over the past few months. By creating an account via http://www.getdropbox.com, you can have any data you choose synced across multiple computers, as well as having a copy in the Internet cloud to view or download from wherever you are. The free Dropbox iPhone app extends the service to your iPhone, where you can view all your files and save your favorites onto the iPhone for offline viewing. The iPhone app is free, and Dropbox offers a 2GB account for free; otherwise you can upgrade to 50GB or 100GB for $10 or $20/mo.

Vlingo is my go-to app for finding anything around me. The voice command functionality allows you to search maps for local businesses, perform Google searches, call a contact, or even update your status on social networking sites without typing a thing. My favorite feature is the maps section. After saying the business name and city, it loads Google Maps to show your current location, and places a pin on the map representing the business. From there you can call the business, view their address or get detailed directions on how to get there. This is probably the app that I use the most often, and best of all it’s completely free.

Flixster is my favorite movie app. You can browse movies by new releases, coming soon, box office, DVD, or just search for a movie, actor or director. You can also view theater listings and watch movie trailers. Two of my favorite parts are that you can see the ratings from http://www.rottentomatoes.com and you can also add movies directly to your Netflix queue. Overall it’s a great free app.

Last but not least is Grocery IQ. This app will eliminate the need for you to ever have a written-out grocery list again. You can easily maintain lists for multiple stores, and the app will automatically organize your lists into the aisles you go to in the store. The app also keeps track of prices, so you can see what your bill is going to be before you even leave the house. It’s a pretty great app, but the only downside is that you have to pay $0.99 for it. From my experience though, you’ll easily make that up in savings by using the app to figure out the cost of your weekly runs to the store.