If it's bigger then it must be better, right? My phobia is buying it all, installing all the bits and finding one of the PSU leads isn't long enough. My last build I ended up running the 24pin across the MB rather than behind it as it wouldn't otherwise reach - and that was (Still is) a Thermaltake 1200w PSU so they would surely expect it to be used in big towers -this was in an Antec P192. My other phobia is air coolers...the most stressful part of my last build was having to use a flat bladed screwdriver to hook the retainers under the clips for a big old Zalman fan. It was the last thing I did, it was late, I was tired and already stressed...and one slip could have gouged a chunk out of the MB. I'm told they are easier now but still like the idea of a self-contained water block to keep things cool. I've had full-towers in the long distant past but never put enough into them to justify one. The top of my current Antec is just the right height for a USB hub, small CD cakebox and so on, a full tower wouldn't give me that much space - instead it would be empty on the inside!
I'm pretty settled on the specific CPU/SSD/HDD/CPU Cooler/Case/PSU but still undecided on the specific GPU (90% certain it will be a 670, 10% 680 but 0% on brand), MB (Definately Z77 but Asrock, Gigabyte or Asus) and RAM - So many options!