Now about cooling in the original case. Some suggestions may apply for larger case as well.
Important things to remember - maximum operating temperature for Phenom II x4 965 BE is 62C per AMD, so cooling is very important, unless you live in Alaska, LOL.
Regarding fan issues in Inspiron 570 and the rest Inspirons (I found that the most of them have the same issues). Inspiron considered cheap model and as such doesn't have software fan control, meaning that BIOS and motherboard are controlling fan speeds, no matter what program I tried, I could not increase fan speeds, even when CPU was overheating. This is part where I am guessing: original CPUs are very low wattage and low heat producers, so BIOS and MOBO adjusted to for those parameters, when we place 965 in, it requires more power and produces more heat, however motherboard doesn't know this and cotinue to operate as if it is still low heat producing CPU (for an example Athlon II x2 250, was running max temperature around 30-35C). So, it is not guessing any more. In order to overcome those obstacles there are 3 ways to control speed of fans, all of them are hardware control, I will discuss all but strongly recommend only one.
First of all let me say about sizes of fans. 92 MM for CPU tower cooler like IceEdge and for exhaust fan. We are talking about 3 fans in total (2 CPU push/pull and 1 exhaust). There is the way to place extra two 70 mm or 80 mm fans, but this is in case if existing cooling system is not enough, because it is a headache, I am done it - I know, will discuss in the other post.
1. Fan panel controllers. The best choice, but requires a lot of work and it will occupy second DVD slot.
Here a 2 examples, I was not testing them, since I went easier and cheaper way. However, if you know the subject it is advised to go this way to lower down the noise level.
2. Another way is to use fans with fan controller attached to them, which is a good idea if you can place those controllers outside the case, usually they have very short cables. This is cheap way, but there are not so many choices, here is Antec Tri Cool 92 mm.
3. This is my way, simple, cheap, but can be noisy - you basically place fan to run at maximum speed at all times, you can do this by bypassing MOBO speed control (PWM) by using one of two choices: 3/4 pin fans where 3 pin goes to motherboard and 4 pin Molex to the power supply, so fan receives full power and runs at 100%, and the second choice is only for CPU fan which attaches to the motherboard using 4 pin (looks like 3 pin) connector, in this case you are using 3 pin fan - missing wire is speed control - you fan is running at 100%.
Here are a few recommendations, I tried to choose not so noisy ones (for me personally I used fans from my old parts, from old Dells).
First, two 3 pin fans which could be great substitute to IceEdge fan if it runs to slow and CPU gets hot (ICEEDGE fans seems to have 4 pin connector, which will be mobo controlled). ARCTIC F9 Case Fan and Rexus TopMotor DF129225BM. If I had to redo my work again and did not have old parts I would use one of them for my CPU push position. Next is the exhaust fan, in this case you MUST use 3/4 pin (2 pins) fan, because 3 pin attached to MOBO and MOBO thinks that it is controlled, but the 4 pin Molex get attached to power supply and thus fan runs at 100% bypassing MOBO speed control. I could not find anything better than this one (in my opinion). CityNet 92mm Case Fan can be found at Frys and Amazon, for the same price. There are more choices like this, but CityNet seems to have better CFM to noise ratio. It also can be used as CPU pull fan, I think I actually used one in my original case.
Now this is how it was looks like in original Inspiron 570 case.
This is Rocketfish 92mm cooler re-branded by BestBuy from COOLER MASTER Hyper TX3, both are almost identical, but I used Rocketfish, because it was available around the corner.
Next is my fault, MSI 550 TI OC card, which I choose due to its exceptional cooling abilities, I should have get 560 TI, but it is too late now
A few pictures to show overall situation. Non modular PSU, well another fault...
Cable management, I hate it.
View from the back angle.
And now the INTAKE fans, yes, you heard it right. I managed to insert 2 80mm fans from inside of the front panel around on/off switch, those fans came from the old parts bin, pictures below shown 2 70mm fans, which I removed due to excessive noise. 80mm fans were mounted using 3 screws for 1 and I think only 2 screws for another (look at red markings), but holding tight, no vibration, here we go:
Front view
View from inside, actual shown are 70mm fans, which already replaced with 80mm (not shown):
Inside intake fan lower below:
I think I covered them all, 80 MM fans, if you decide to install them you would have to connect them directly to PSU.
There are a few suggestions in this department - if you feel comfortable only - drill holes in case.
First - lower part of front plastic panel for those intake fans to get extra air. Without those holes I felt some help as well, my temperatures were going down after testing much faster, compare to case without them.
Second, drill the holes in the bottom panel right under hard drive location, it was done by on user, however he did not post any pictures, so I don't know.
Third, make a holes on the side panel and install extra fan there, will help a lot, since Inspiron 570 is very air tight case.
Forth, make holes in upper panel for extra exhaust fan, will help a lot.
Fifth, one user reported placing water block inside, but again no pictures provided, unfortunately.
This is about it, I think I will look into a few parts here for some fan model recommendations, but overall this reply looks complete to me.
Next will be discussion about larger case.