I like the T Mobile and Nexs 5 combo. T Mobile began separating the cost of the phone from the cost of the service. The Galaxy 5 is $660. You can buy a used Galaxy IV for about $300. I don't think the new version is worth twice as much as a phone that was released a little less than a year ago.
I think that by separating the price of the phone people will start realizing that they are paying significantly more than the $150 down for their phones. Hopefully, this will put downward pressure on phone pricing.
The Nexus 5 is also a great value at $349/399. It's specs are about 90% of the new phones being release for much less money. It also is the 1st to receive updates and does not have the bloatware.