When I upgrade, I look for significant increases in performance.
Ivy Bridge is the next major upgrade. I can't see the need for updating my system until then. When I do, I'll throw together another thread like my previous two (first thread forever lost, 2009 upgrade
here ) PC projects with explanations, charts, etc as to why I chose what I did. Usually it includes cost/value and performance comparisons. As you can see from my last thread, It will have served me well for three years at a decent price. No need to go ass-crazy buying the top of the line stuff if you do your research.
I'll probably shoot for around a $1-1,500 price tag, not including a monitor depending on value points.
Couple things:
I use 46" LCD 1920x1080 TV as my main monitor. It's awesome and I can't see myself going smaller ever again. I'm older and it's hella easy on the eyes with a monitor that big and big screen PC gaming rocks. These days you can get a 46" LCD TV dirt cheap (under 1K) with excellent quality.
If I replace my 1920x1200 side monitor, it will be with a Dell or Apple 2560x1440 res screen. I've had the iMac 27" screen a couple years now and it's just another thing I can't go smaller on. They're under 1K now so not that expensive.
My Raid SATA Tower still only has four 2 TB hard drives (2x2TB mirrored sets) with eight HD bays total. I only have good things to say about this setup. Worry free mirrored backups. If I run short on space, I'll get another set of 2 TB Hitachi drives and mirror them...or four more but I don't want to spin drives 24/7 if they're not being used. This is my last non SSD mass storage solution so it's gotta last until SSD is cheap enough (I'd pay 250.00 per TB for a mass SSD solution). Consider USB 3 and Thunderbolt external storage solutions in the future. SATA is fast. That's why I went with it. Plus no Trucrypt mounting issues.
iPads rock. I have 24" PC, 27" iMac and 46" PC screens and I still have an iPad on my desk usually running a stock app or something else. Around the rest of the house, I use both iPads. In bed, I have on iPad typically playing ambience (rain, waterfalls, etc) for sleeping/relaxing. The other iPAd for browsing news (Zite), watching TV shows or Movies (streamed from main PC using Air Video) or Netflix. iPhone still best for IM/SMS stuff and it's my backup alarm clock. I still don't know anyone, even skeptics, that actually own an iPad that don't think it's awesome for multimedia consumption. I'll buy the iPad 3 day one as well if it has the retina display upgrade. Consider buying one a secondary device.
Least used device: iMac. It's great for iTunes and jailbreaking my iOS devices, and watching very hi res/bit rate movies on that awesome screen, but it's not going to be my main PC anytime soon. I do see a lot of benefit now to possibly buying a Mac portable device (Macbook Air, etc) with the new Tiger OSX. The multitouch features and more iOS-ish feel to OSX Tiger work excellent on something with a trackpad. Even so, I'd want to game on my laptop so I'm thinking of pumping out ~$1,750 for a high powered laptop like the
ASUS G74 or
MSI GT780R-012US to have something for the bedroom. I'll probably wait for IVY mobile solutions though.
My suggestion: wait for tri-gate if you want the foundation for a PC that will perform well for 3+ years as it appears it will offer a significant boost over current systems. Couple it with whatever "upper-middle-class" level video card nVidia releases around that time. RAM is cheap so go for 12 GB. SSD is a must for your OS drive. Find a quiet case. Buy the best LCD you can afford.
Also remember: there's tons of poor people or clueless PC people out there. The Gaming companies can't afford to leave them behind so your PC will always be sufficient if it was purchased within 5 years and wasn't a $300 Wal Mart special. We're heading into the second half of the recession so that's not going to change. Pick a price and research a value build to fit it, picking out the few expensive parts that actually make a big difference in performance.