Mine has been a viable step from my D1. The LCD screen is arguably better than any of the 4 phones in the op. It can easily get you by for 6 months until more options are available, and you could then sell it for nearly what you paid for it. The price on the new phones on your list will all del by $100 or more so the used phone route makes sense. Plus you would get an HTC SENSE experience.
The TBolt is good, but the Dinc1 has less issues and a better screen. Find one for $75 and enjoy.
Sent from my ADR6300 using DroidForums