Yes, and no matter what computer you own, as software advances, it will require more space/memory/cpu computing to perform the more advanced tasks. In that case, there's really nothing you can do about it except for upgrade your hardware.
iMacs last for life.
What's your experience with laptops, or computers in general? How long do they last?
My first computer was an 200 Mhz HP desktop computer my mom bought me from the now-bankrupt Good Guys when I was 11. A 500 Mhz model came out for the same price within a year.
I've had another HP desktop, a Dell laptop, a Gateway-Acer Netbook, and now an iMac since then. Also, various computers from various jobs. In general, I can tell you to avoid a laptop unless you realistically need the portability. Their a little slower than what you can find in a desktop for a cheaper price. Besides, if you ever needed a laptop, you'll still have your old one. And yeah, 4 years sounds about right, although my cheap Netbook was slow from the very beginning lol. My desktops kept up to speed much longer than my laptops did.
The laptop craze is understandable though, people are tired of dealing with the tower and monitor, a laptop is simpler. But the iMac has the CPU embedded in the monitor, so you don't have to deal with that problem. And even Windows-PCs have a similar setup now, at Black Friday in Best Buy most of the PCs I saw on display were basically big tablets with a stand to hold it straight with a mouse and keyboard hooked up to it. And you can still treat it like a touchpad when you want to (which will be useful when Windows 8 comes out because it'll have a separate operating mode just for tablets, you'll have the best of both worlds). It's pretty cool
I'm just wondering if I'm fighting a losing battle and it's time to buy a new one.
Go-for-it, go-for-it, go-for-it. There are some great post-Black-Friday deals going on right now. Been back to Best Buy a few times for some PS3 games after I bought my iMac and there are still tons of people buying computers. The After-Christmas sale is the least-popular biggest sale of the year that gets the least media attention.