My personal experience and situation right now probably can sum it up for you...
I built my now defunct desktop in college in 2002. It had one of the brand new AMD Athlon64 chips featuring Socket 939 architecture. It was awesome when it came out and blew everyone else away. I managed to make a couple bucks doing it too, because word got around campus that I knew my way around a motherboard and before I knew it, a bunch of people were asking me to build them computers for a small fee
Fast forward to 2004. I bought my iBook G4 because I didn't want to lug the behemoth 1000 mi. each way to and from college for vacations (and I didn't trust the housekeeping/maintenance staff that would "visit" during extended vacations so I didn't want to leave it there).
At the time, the iBook was also awesome and blew away comparable laptops.
Fast forward again to the late 00's. Internet content had evolved so much in around (or less) than 5 years that I couldn't partake in it. While 5 years' worth of life on any type of high-technology equipment is admirable, I did get a bit disappointed because I was expecting a little bit more life out of it.
Same issue with the Desktop. Soon after I bought it, they changed to Socket 939 architecture and eventually AM2, and you then saw dual and quad cores launching. DDR2 and DDR3 appeared. PCIe popped up. SATA2 appeared. It just wasn't worth upgrading the desktop.
Even the Macs had a major fundamental change and moved to an Intel processor.
So, to summarize what I meant by all this:
Unless you have any idea what will be commonplace in terms of your internet browsing experience in 3 years from now, I would suggest you wait.
I am expecting to have more of a shift from traditional means (television, magazines, etc) into more of an internet push. Why watch the weather channel for 10 minutes to see your local forecast when you can crack a laptop or smartphone and get your information instantly?
Further, with the advent of HD a few years ago and how common 720p & 1080i are and how much they've come down in terms of cost, I wouldn't be surprised to see a lot more streaming content now for computers in HD.
Considering my graphics card in my iBook can barely load up the Facebook flash games, I would be weary about buying a lousy, old video card if you really want to get more than just a few "years" out of this thing.