I know this post is dated & the OP has probably gotten a phone, but... For future reference, here's my 2cents...
1.) look into the various carriers in your area. Who has the best service? Who has crappy service in your area? You could get the biggest baddest must-have "IT" phone and pay $60+ bucks a month for service... But if the provider you picked has weak to no service where you'll be... Do you really want to invest so much into what'll essentially be a paper weight?
2.) Decide if you want a smartphone (the numbers I saw indicate over half of the US mobile subscribers have one), or do you just want a basic feature phone?
3.) Once you've got an idea of the type of phone you want & the carrier(s) you may be interested in, go to their stores. Play around with the display models of the various phones. Hold the phone in your hand, see how it feels - is it too big? too small? too bulky? does it feel like a piece of cheap quality plastic you could snap in half if you accidently sat on it? Are the buttons too small for your fingers? And of course, play around with the OS some. Can you figure it out? Reading online reviews of the various phones you might be interested in as well could help.
I'm not too versed in feature phones, but if you do chose the smart phone path, here's some hopefully useful tidbits...
iPhones user interface and form factor are essentially the same from the first to the most recent, though the newest (5) does have a slightly larger screen. If you chose the iPhone, I would say go with at least the 4S. I've heard iPhone users say 5 isn't that much of an improvement over the 4S and the 4S will be slightly cheaper now that 5 is out... And with 4S you'll get Siri, Apple's digital voice assistant.
My knowledge of Windows phones isn't that great. I believe there are a few, with different form factors & hardware specs. But the OS, like the iPhone, should be the same across the board.
I am, however, an Android fanboy so I can pontificate for awhile on choices here. First off, unlike WP7 & iOS, the Android OS will vary. First, they don't all get updated at the same time. About half of all Android devices are still using Gingerbread (Android 2.3). Phone wise, Ice Cream Sandwich (4.0) and Jelly Bean (4.1) are also available, and based on rumors I've been hearing, 4.2 may be out soon as well. Each phone gets updated on its own schedule between the manufacturer and the carrier. Older phones will probably be stuck with 2.3. If the phone was released in '11 it'll likely get ICS. If it was released in '12 you'll likely already have/soon be getting ICS & probably will be upgraded to Jelly Bean. Additionally, each manufacturer (HTC, Motorola, LG, Samsung, etc) applies their own customization (or skin) to the OS to differentiate it from their competitors. So a Gingerbread phone from HTC will look and act differently than a Motorola Gingerbread phone. There is also a rare breed of phones that bare the Nexus brand. While they come from various manufacturers (Samsung made the last 2), their OS comes straight from Google, lacking any customization. They'll also generally receive updates within days of it being released (while non-Nexus phones will wait months to years before being updated officially).
Like the OS, Android phones vary greatly in hardware as well. Screen sizes range, I believe, from 3.5 inches to 5 inches. There are single, dual and quad core processors running the phones. Few have physical keyboards, most just touch screen. Some have removable batteries, others don't. And batteries will vary in size. Usually in the 1700-4000mAh range - which, depending on usage, may last from half to a full day of charge (smart phones really aren't the best battery wise) [you can generally buy extended batteries for phones with removable batteries to help them last longer]. All older phones & some newer phones will have a microSD card slot for removable storage to supplement the phone's own internal storage (usually 8 or 16GBs). If the phone doesn't have an SD card (Nexus phones & some newer phones), it generally has 32GBs internal storage (and now possibly 64GBs) to make up for the loss of expansion. NFC is starting to become standard - allowing you to share files & use your phone as a credit card - by placing it in proximity to other NFC enabled devices.
