The 17" LCDs I bought 4 years ago.
The 24" LCD I bought one year ago.
The mouse I bought 4+ years ago.
Speakers/headphones.
As has been said, it's worth investing well in some parts of a computer, the parts you will use for a long time and use a lot.
Good monitors, good mice, good keyboards, all worth the investment.
Everything else is a throwaway part that will be outclassed and obsolete far more rapidly.
(Unless of course you use your computer for money making tasks e.g. you do video shoots and edit/encode on your PC, in which case things like super fast CPUs now will be more worthwhile)