like they said... unless you're a gamer (or perhaps do a lot of CAD or graphics rendering), it's going to be a long time before your computer is obsolete.  Of course, it's already obsolete by the standards of the people who shell out thousands of dollars needlessly so they can brag they have the latest and fastest computer.   And, it's already obsolete by the standards of the people who want to sell you a new computer.   
However, I've said it before and I'll say it again.   90% of computer upgrades are pointless.  The majority of people do little more than email and a little bit of web surfing.  My inlaws are about to upgrade, because their 1 GHz machine is "too outdated and slow" to surf the internet on.   I say, it's far faster than they need.   It's just "broken" because it's so full of viruses and spyware (again.)  But, my advice won't be taken and 2 years from now, their latest computer will slow almost to a halt because of viruses and spyware, and again, they'll need to upgrade so they can read their precious Fwd:fwd:fwd:fwd:fwd:fwd: emails, surf to the cards sent to them online, and play solitaire.