my current pc will be 2 years old this christmas. before it i had another one, i tend to upgrade every 2 years. this year, i will probably build my own, since it will be easier to upgrade this way. with name brand computers such as dell or compaq, you cannot switch out processors or motherboards because they are wired differently, thus you must buy a whole new computer when you need more power (other then the graphics card) if you build your own computer, you never need to do a full upgrade, you'll probably need to upgrade a part of it every year or so (one year, upgrade the graphics card, next year, the cpu, next year, mother board, and so on)
oh and mah, sorry, it will never die. i dunno why you said that, with series like doom and half life and everquest and diablo and warcraft, there will always be pc gaming. if anything, it will cause console games to die because almost any console game can pretty much be played on the pc with better graphics and sound.
thats cuz nothing big has come out for a while, just wait for later this year. half life 2, doom 3, everquest 2,max payne 2, they are all gonna sell like mad.