Power Supply Unit

Seasonic x-750 or ss750Ht. Cm and corsair make shitty psu's . U need UPS if u have power shutdown problems in your place.

The Seasonics are definitely good, but 750w is totally overkill unless you're using multiple GPU's.

link

Theres a handy calculator in the link above to figure out how much power you need.

A recent round-up of 300-450W PSU models.
Even if you need more power, you can still get an idea of what to look for in a PSU.

I'd reccomend a UPS only if your house is prone to blackouts and/or has a bad electrical line and/or you must be sure not to loose unwritten data for job/study reasons.
An occasional shutdown won't damage your PC.

You won't need more than a 500watt for a single card system, anyone who says otherwise is ill-informed or an idiot.
Good cheap brands are: Coolermaster, Corsair and OCZ. The best brands are Seasonic and XFX.
You should look for 80plus bronze and better.
That's all you need to know

coolermaster is a bad brand for power supplies. antec and corsair are okay. seasonic and xfx are good brands for power supplies

I have Corsair 1200W 1200AX 80+ Gold

Personally I have a UPS because I live out in the sticks, and suffer from fairly frequent power outages. For most users, there's little need for one though.

In terms of a PSU, make sure you get a recognised brand (don't be tempted to go for a "no name" because it offers twice the wattage at half the price...). Also get one that gives you a bit more power than you'll need. Better safe than sorry :)

I have a Corsair 750W 80+ Gold power supply. Its over kill for my system, but its better to have access to far more power then you actually use so that you can do upgrades easier in the future.

I went with this power supply because it was on sale, but I had done a lot of research on it. It will work good even in a room temp of up to 50 degrees Celsius, most others are only good up to 40c. It has a 5 year warranty, lots of good reviews. The only thing I dislike about it, is that its not a modular one where you can just plug in the cables you need.

As for UPS, I have had many over the years. They have all been APC. They are more expensive, but over all I find the quality good. I have a Back-UPS Pro 1500. I would not say its over kill for my system, it gives me about 20 to 25 minutes of time where I can shut down my system. This gives me lots of time to close down what ever I am doing and it also gives me enough time to just wait to see if its going to be off longer then a couple of minutes.

What I like about this UPS is that I can get a second battery pack, which I can plug into the back of this one which doubles or triples the time I would have to shut everything down.

Its very quiet, I have not heard the fan in it once. It allows me to turn off all the warning beeps and stuff. I can see the voltage going in, an estimated runtime on just battery, how many watts my system is using and lots of other useful info all on a LCD screen on the front of it.

The main reason I have this is because we have had many brownouts. Basically where the power goes off for just a few seconds. But in that few seconds it will shut down your system hard and that is not good. Even if you don't have these, or don't have blackouts often, having a UPS is always a good idea.

One secondary reason I have it is so that I can have one light on in the house for up to 90 minutes if the power goes out. That gives me time to go get a flashlight and/or candles which are near by but annoying to find in the dark. :)

I use Ultra PSUs, ive never had an issue that and they have a lifetime warranty attached to them too if you register the unit