So basically for performance, character creation e.t.c.

I'm getting a PC in December so I want to be prepared

And modifying*

Well... there's a few thousand that fit into that category.

http://www.gamesas.com/index.php?/topic/1060141-mod-recommendations-for-new-players/page__hl__recommendations - Links and info on patches.tools you'll need.
Info on how to find any type of mod you want. etc

CHeers!