I'm planning to buy the arduino, and I was wondering if one, will I need a keyboard to power this and for my second question- which relates to the Pi as well- will I need a soldering iron to be able to program things LEDs to light up or motors, or can I still program components using the arduino without soldering.
As Loko says, it depends what you want to do.
You can connect the GPIO pins to a breadboard, and then connect individual electronic components to the breadboard without doing any soldering. The arduino and the pi are the same in this sense.
I imagine you can go a long way in learning the fundamentals of electronic compenentry doing just that. Soldering is necessary if you want to make a more permanent assemblage, or if you want to connect another board that doesn't already have breakout pins attached. This would include various small sensors, complex arrays of LEDs, etc.
If you want to experiment, then many components come in 'through hole' 'leaded' (with wires not with Pb) packages which can be used with a solderless breadboard. You can get connectors for the gpio pins to use them with a breadboard.
ICs that come in 0.1 inch dual-in-line packages can be used with a breadboard, but a lot of modern ICs are only available in surface mount packages. Unless someone solders them to a 'breakout board' you can't use them with a breadboard. Even then, you may have to solder header pins to the breakout to use them.
If you want to make a permanent project then using a breadboard is a waste and unreliable. You will either have to solder or wire-wrap it. Soldering is the easier option for most cases.