What components to get apart from Arduino ?

I am a noob to both Arduino and electronics. I got a UNO-R3, and have been playing with the sample projects - but as I got addicted, I feel my UNO board is not enough... there are examples to control ethernet, sound, motors and multiple things I am new to.
My request is for some suggestion as to what new things am I supposed to add to my kit - for now I have just some wires, LEDs, resistors and capacitors. These are what I can think of :

  1. Potentiometer
  2. Speakers
  3. Light Sensors
  4. Servo Motors
    But I am not sure should I buy all of them.. or any particular configuration I should look for.. or I need some other important stuff ! Would like to know what the community did after getting the basics of Arduino.

Thanks in anticipation !

By light sensor I guess you mean like LDRs?- Light Dependent Resistor? They're fun.... I stuck one on the end of a servo horn and had the servo "hunt" for light....

I'd get a few small transistors too, BC547 style. You can then pretend the LEDs can't be run directly from a digital pin and switch them on and off with a transistor as if they were "real" plant as shown here.

Maybe also a couple of cheap toy DC motors, run them with the transistor, remembering to read up on the need for a diode...

Have a search across various Arduino supplier sites- they tend to have pre-packed sets of odds and ends.

JimboZA:
Have a search across various Arduino supplier sites- they tend to have pre-packed sets of odds and ends.

This.

Lots of vendors, such as Sparkfun, Adafruit, etc., will have "experimenters" kits, or fun project kits. Check out things such as parts grab-bags, etc., such as at Yourduino. If you want to play with motors, Adafruit has a motor shield kit. With a lot of surfing, you can find things more cheaply than buying the kits from Sparkfun or Adafruit, but until you have learned a bit, the kits can be easier than buying parts from Mouser, Dip Micro, Digikey, etc. In some cases, the kits could end up being cheaper, especially if buying from Asia.

Rotary encoders are fun to. And a serial LCD display can add a lot of utility to your creations!