How many photos and apps will you be putting on it? Personally, I’d get the biggest one I can afford so there’s no worries about that. Now, a few GB can hold a lot of photos. Still photos are only about 100K or so, so you can store thousands per gigabyte. Videos and MP3s, on the other hand, gobble up memory like mad.

And say ‘hi’ to Siri for me :-p

I have over 200 apps on my Droid X and still have about half of my 24 Gb free, but that would go away if I put my entire music library on. Given that the iPhone lacks storage expansion, I would go with the 32 Gb (or something that had a micro-SD slot, like an Android)

As for the data plan, unless you stream video, 2Gb/month is plenty. I surf the net a couple hours a day on my phone, and I manage to stay well under that even streaming internet radio.

I have the “32GB” version (which actually has a user capacity of 28.5GB). On my about page it says I have 1,279 songs, 1,122 photos, 170 apps, and 39 videos (7 of which are full length movies, the rest are shorts, featurettes, or videos I’ve recorded myself). I have 3.9GB still available.

As for data, I’ve never gone above my 2GB/month limit. I don’t stream video while on the 3G network, however. On the other hand, I am constantly using the phone for apps, music, and iMessage, regardless of where I am.

It is better to have too much storage space than not enough. Especially when you are juggling a photo library, a music library and an app library. (Some apps can be pretty huge, especially if you like games—Infinity Blade II is near 1.5GB) The iPhone does not have expandable storage, so you’re stuck with as much as you can afford.

As for data, do you plan on streaming alot? (Pandora, Spotify, Netflix, etc) Then definitely go for the 5gb. But if you’re only going to do basic browsing, and using apps that interact with the internet, then 2GB should be finef or you.