should i buy iphone 4 now or wait for the 4g model or wait for the 5g model or wait for the...?

it depends on what device you own at this time. If it's a new cellphone (you bought it up to 1-1.5 years ago) don't buy it and wait for the next one. if you have an older device, buy it. :)

in my mind there's a few things you might want to consider. First of all, I've heard on the radio that the first year could cost you $2,000, and if you have that kind of money to burn then sure go ahead, but most of the country is on unemployment compensation which funds are running out so if yours runs out then your credit will be ruined. And, is your job secure? The next thing you might want to consider is, are you employed and if so then does your income cover this kind of "want" since it's definitely not a need and at this point no matter where you are in the world there are tough times ahead and people are selling what they own to make ends meet, to pay the mortgage, to buy food. The world's credit card bills are more than $10,000 per person; have you learned to budget, can you afford yourself? If you've passed the above test, then sure, go buy your toy.

Get a droid. iPhones are for douchebags.