They're remarkably simple to put together. Everything pops in, or slides in and screws in. Give us an idea what you'll mostly be doing (or want to be doing) on your new system, Tigress, and we can give you some good suggestions for system specs.
I'm going to be using lots of different graphics programs such as Adobe Creative Suite, Maya, Sketchup, AutoCAD, Revit, and so on and so forth. I will be storing a lot of photos and images/files created from those programs. I need to be able to run lots of programs at once without my computer going crazy.
I also want it to be fast when I surf the net, stream music, watch videos, and get back into MMORPGs (mainly Gunbound)
I want a big screen to double as a TV, or I might get a TV and have it double as my monitor. I also need about 10 more USB ports, because 2 is just pathetic.