PSU is the only component holding my current system back. Never owned a Seasonic PSU before but I have heard great things about them and I'd love to own one...in fact, I'll probably buy one unless I win one! :-P
I have 2 systems with X750 Gold PSU that are on 24X7. One is a little over a year old & the other is over 2. These PSUs replaced 2 failed units that also took out the m/b. I will only use Seasonic! The next system in planning will have a Nvidia Tesla M2090 GPGPUs ... maybe 2. Add on even a mediocre graphics & I'll need a very good reliable PSU.
Because the last time I bought one was back when I had zero responsibility in life. So nostalgia. That PSU is still kicking to so they do make good stuff.