It just makes the computer faster to use overall. I thought I could get away with using a Western Digital Black 500GB in the desktop I'm using now, but after using a laptop with an SSD for 4 months and getting used to how fast it boots and loads programs I feel like I should upgrade. But if you don't care too much then the one 2TB should be good enough or you could even go smaller if you don't plan to store that much stuff.
You can use a smaller SSD, but I prefer to use a 120GB SSD so I can at least store SOME stuff on it, like programs, music, some video, whatever. You can use something like a 60GB SSD, but I think space would run out really fast after installing Windows 7 or 8 (both of which should take up like 20GB).
As for the video card, I just assumed Skyrim took a lot of power to run so I chose one of the stronger card I could find. Just read this if you want something else -
http://www.tomshardware.com/reviews/...view,3107.html