I just wanted to add two quick things. The replacement for the Pi isn’t expected until 2017, so you should only expect to see incrementially upgraded versions until then. Also, the Raspberry Pi B+ is still the same price as the original, $35.
"The Model B+ uses the same BCM2835 application processor as the Model B. It runs the same software, and still has 512MB RAM; but James and the team have made the following key improvements:
More GPIO. The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model B. More USB. We now have 4 USB 2.0 ports, compared to 2 on the Model B, and better hotplug and overcurrent behaviour. Micro SD. The old friction-fit SD card socket has been replaced with a much nicer push-push micro SD version. Lower power consumption. By replacing linear regulators with switching ones we’ve reduced power consumption by between 0.5W and 1W. Better audio. The audio circuit incorporates a dedicated low-noise power supply. Neater form factor. We’ve aligned the USB connectors with the board edge, moved composite video onto the 3.5mm jack, and added four squarely-placed mounting holes."