Ok, we all have our personal favorites.
Personally, I was thrilled to get rid of mine.

I'm hoping to get around $200 for my iPhone 4 which is in perfect condition and never left an Otterbox Defender case.
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I currently have a 3GS and T-Mobile. The "3G" is slow at times, but I don't need it very often. If I need to use the internet, I'm usually near a computer or in wireless range. I get a good phone, integration with my iMac, apps, and some internet when I actually need it.

$50 per month compared to $100 is also a huge plus. It would cost me an extra $600 per year to roll with AT&T.:-)

Now, if I was constantly on FB then this phone would not suit my needs, but I'm not.

P.S. My phone has not dropped a call once since I have owned it.
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According to t-Mobile, by year end their spectrum should be switched so that all iphones can use the 3g speed, not just EDGE.

I currently use my iphone 3gs with EDGE, on a grandfathered $10/mo unlimited plan. While the iPhone 3GS isn't the fastest phone in the world, it does everything I need it to do, and I can afford to wait one second for something to load. ("It's going to SPACE!" lol).
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The problem with the 3gs being so many gens behind is it's about to be left out of some of the iOS updates and many newer apps that come out when iOS6 comes out will not work on the 3gs.
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Missing out on some of the newer apps may or may not suck. My phone is jail broken, so I haven't updated the OS for some time now, but it works fine. Well, everything except for iBooks works fine.
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Personally, I follow the principle of "Pick a phone you LIKE and are COMFORTABLE with, and BUY IT! (damned the cost)"

But I typically hold on to phones for years past a contract timeline, and Verizon won't give me subsidized upgrades anymore since I adamantly refuse to give up my unlimited data plan. :-)
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