Hello guys
I am planning to build a PC system by my self for the first time,with the following specs.

Core 2 Duo E8400
Asus P5N-E SLI
Corsair XMS2-DHX 4GB (2x2GB) DDR2 800MHz Dual Channel Kit
Western Digital Caviar SE16 640GB + WD Caviar 500GB
XFX Ge Force 9800 GTX+
APC Back-UPS RS 800VA 230V (540W output)
In addition i already have ,1 HP usb printer,17 inch CRT monitor also.

Now this is where i am getting stuck,i can't figure out which PSU and cabinet to get.
I had decided to get cooler master CM690 with cooler master eXtreme Power 500W.
But i keep reading that this PSU is not that good,is loud.

Now, I want to know is my configuration compatible,is the eXtreme Power 500W overkill/under kill for my system,and is the cabling in this PSU compatible with reverse ATX of CM690 (PSU being at the bottom of cabinet) meaning is it long enough.
I calculated my power reqs http://extreme.outervision.com/psucalculator.jsp
Please i really am getting nuts over this thing,the more i read the more confused i get.
If this PSU isn't good enough then what do you suggest for CM690.
An Antec EA 650 any good or CORSAIR CMPSU-620HX 620W PSU or something else.It should have long enough cables since for CM690.
And also since the UPS has 540W output capacity,will having a 540W+ PSU have any issues over there.

Hope you guys provide the help that i need to make the final decision.

You probably want a nicer Power Supply. I did my first build not too long ago and the PSU was the biggest issue. I tried 3 of them out before finding one I liked. Always have to worry about heat, noise, performance, power consumption.

I stuck with the OCZ EliteXStream 800W. Quiet, runs great, a little warm, but what 800W PSU isnt. PC Power and Cooling got purchased by OCZ, but they are good as well. Corsair is up there. I would say anywhere in the 650-800 range is good just for future proofing incase you want to add more video cards, or harddrivers or do any overclocking.

As for the card you chose there, its gonna be great. I have the 8800GTS 512 in SLI and it is very similar to the 9800GTX, though the plus version will be a little better than that. Might want a new monitor to take full advantage of your new card. 22" Acer is on sale for like 200 at Newegg. Any higher than that resolution, you might wanna SLI the cards. I have a 22" Samsung right now, but want a 24" as well since I have the SLI to back it up.

Cases are personal preference usually. People will probably recommend a bunch of good ones. See mine below. Has some blue LED's but not too nuts and a nice door with decent cooling. Was good bang for buck.

A few standard recommendations:


Hiper 880W
I realize you have not heard the name, but this is a quality PSU at a very reasonable price. It's reviewed here at the best PSU review site anywhere. It's enough power that you can run two of your cards in SLI, with a healthy safety margin and durability.

Other possible choices:
Corsair 750TX
PC Power & Cooling 750

You may think this seems like overkill. There are other things to consider besides wattage however, as already mentioned. A PSU that is working hard gets hot. The longer it's hot the shorter it's life span. A quality efficient PSU gets less hot over all. If you buy one that is just good enough now, you will replace it on the next build. Often cheap PSUs deliver poorly regulated voltage, resulting in damaged parts or computers with mysterious ailments.

I bought my PSU when it was considered an insane amount of power, many years and 3 builds ago. Now it's just adequate.... yet it's still working.


Case:
Tempest
This popular case has great air flow and is priced in the right range. Maybe too flashy.

Antec 300
Inexpensive and popular. Good design and air flow. Not large, but adequate for most builds. Good price.


Your UPS will work fine with your new system. Your new power supply will likely never pull 540W because it is at least 80% efficient, and at any case that's just the rated wattage it can deliver X number of minutes at.

I'd get the CM690 without PSU, and combine it with a 750TX. Also, get rid of the WD 500GB and get a second 640GB instead. It's a few generations newer and faster.

The P5N-E SLI is a rather old model. Newegg doesn't even sell it any more. I'd rather get an Asus P5Q Pro. That's based on a more stable and much newer chipset (Intel P45) and overclocks very well.

If you want a system with two video cards and get the P45 then replace the video card with an HD 4850.

Thanks so much for replying guys,really appreciated it.
About the OCZ 800W thing,2 problems,
ocz not readily available in my country might well have to be imported (not an option)
Isn't 800W/750TX overkill,considering i don't plan on overclocking (ever,don't have the nerves ) and I won't be using Graphics cards in SLI although i am having a sli enabled mobo (sounds silly,ya i know) .I'll use only 1 card.
And also,corsair 620W one has got peak wattage output of around 700w,i think,not sure though.
Same with Hiper,its not an option in my country,too much hassle.
Thanks for clearing up the UPS issue,i am relieved there,thanks you guys.
OK I'll do the HDD thing.
About that P5Q pro i heard/read that its got some cooling and voltage issues,and blocks sata connectors.
Is Intel P45 better than nforce 650 series?
So is i were to use the CORSAIR CMPSU-620HX 620W would it complete my configuration and is its cabling adequately long enough?

Oh sure, If you are set on doing it that way, the Corsair will be great

Yes, the 620HX has very long cables and it's one of the best PSUs out there. It's got plenty of power for that setup too.

Yes P45 is better than nForce 650i. However, if you don't overclock, the 650i will be OK too. If the P5N-E has all the features you want and you get a good price go for it, no worries.

Once again thank you all so much.
billin30,Proximon,aevm you guys rock
Now i have no confusion,i got my rig.