Ah yes, a new machine is a joy... well, not forever, but certainly for a while, until it's no longer powerful enough to run the software you want to use. A few years, if you're lucky.
I just replaced my old PC, it was 5 years old and showing its age (eh, so am I...), so I bought new components--case, power supply, motherboard, CPU, RAM, video card, monitor, and disk drives--and built it over the last three days. Actually I built it in one day, took me two more days to figure out the optimal BIOS settings for everything with a lot of trial and error. And while I was at it I upgraded my Internet connection to 5 Mb/sec from 1.5 Mb/sec because my ISP had a special promotion going on. A joy indeed, this thing is blindingly fast, and almost inaudible. The cooling fans in the old one were pretty loud.
Interestingly, I found that on the whole it's cheaper to get everything from a local vendor than it is to order online from places like Tiger Direct. Certain components, especially memory, are much cheaper online, but for a whole system, once you factor in the shipping and handling charges, online doesn't appear to be the way to go. I'd go online to buy certain upgrades, like two more memory sticks or one more 500 Gb SATA drive, but for big pieces like a case or a monitor, the shipping charges will kill the budget. And if you buy from a local vendor, you've got some place to go, with real live people to talk to, if something doesn't work.