DescentBB

OK, in the end I got a GTX 650 for my Core i3 computer. I decided to buy a new fan for the read side of the case, I put it as intake to mantain the interior of the case cool.

Is that a good idea, or it should be better to use it as exhaust?

Is a simple case, just has a rear fan slot (no front or top) and a side (left) one. It doesn't has any fan installed in the side.
Overall I get temps of 35° to 40° on the CPU and 35°/36° on the video card when browsing, around 58° when gaming as it is now.

So, I leave it as it is (rear intake) or change it to rear exhaust?

The only thing to avoid with fan placement would be having two fans blowing against each other. So for instance CPU fans usually are oriented so they blow from the front of the case towards the back, so you wouldn't want an intake fan blowing back at the CPU cooler.

Otherwise either way works.

Well, it's not pointing towards the cpu fan, but it is basically at the same height level.
The CPU has the stock Intel cooler with its fan, blowing towards the CPU (as far as I can tell).

From a top view of the case, air is flowing like this:
The video card is pointing downwards just below the rear fan, with its fan flowing to
the base of the case.

So it's everything OK like this?

Stock Intel fans blow down, so that setup is fine. Only thing to keep an eye on is the HDD temps, if they get over 50C it might be a good idea to put a exhaust fan next to them that would pull air over them and out the front of the case. HDDs like to be between 35-45C, outside that range the yearly failure rate goes up by ~5% (which is a pretty small difference, but still shows up in statistics over time).

My HDDs are at 36°/38°, so it seems everything is OK.

Thanks once more for your help Krom, your posts are always very enlightening!