Is there still a problem with the 101 being almost too new for the programs. I've seen a lot reviews about library's not supporting it and what not. I know I should probably get the uno but I can't help myself but be intrested in the 101 since it's better overall and includes a gyroscope/accelerometer and it's only $5 more than the uno. (Looking to get my first set up in this, so I don't have anything yet. Trying to find what to get)
The 101 has it's own section in this forum : http://forum.arduino.cc/index.php?board=103.0 As far as I can tell from this forum, the 101 is not yet completely mature.
The Arduino Uno is the most basic Arduino board to start with. Many fun libraries have been created for it. However, if you want to add more sensors, then the 5V Arduino Uno might conflict with 3.3V sensors.
If you want to play a little with a beeper, a led, a LDR and so on, then use an Arduino Uno. It's a great way to start to learn about programming and electronics. If you want to be up to date, then use a 3.3V Arduino board, for example the 101.
Another option is the Adafruit feather series. Click here and be amazed : https://www.adafruit.com/feather