I had two fans. A yate loon DS12 was mounted vertically on a Scythe Mugen. I also had a Scythe SY1225SL12LM-P mounted horizontally to the top of an Antec 180. Both are dead.
A second Yate Loon is still running on the Mugen, as well as a Nexus DS12 on the back out of the case. What would you recommend I replace the dead ones with? I'm afraid to invest again in either of these models seeing these dead ones here.
Noise isn't exactly as huge a concern for me anymore due to a new apartment. I also am running up against my overclocked 4.2Ghz i5-750 heat wise. Any general recommends? I'd like to keep price down as much as possible, as these fans appear to die. I may be reponsible for their death. I don't know whether the DS12 can be mounted vertically. Also, the Scythe had accumulated quite a bit of dust as it sat on top of the case.

Thanks!

If you want affordable, I had a good experience running Arctic Cooling F12 PWM as case fans in my P180. Both horizontal and verticaly mounting worked out. Only trouble I had was when I poured a glass of water on them.

They don't have those fans on the official AC site anymore, but might be some good successors to pick from - or maybe you can find the old stuff on sale still.

After that, I think Slip Streams might be the next step up, and you can hardly go wrong with a Slip Stream.

For horizontal placement consider real ball bearing fans, the should last longer than standard fans in horzontal placement,

Fan Roundup #6: Scythe, Noiseblocker, Antec, Nexus, Thermalright

From the conclusions on the review,

Now what you need to decide is what rpms you need, i had 5x 1850rpm version, and i had a fan controller and at 600rpm they are very quiet fans, i think i was able to drop them to 400 or around there before they stoped with the fan controller. My advise is go with the 800rpm version and undervolt it if you need it or if you cant find it, the 1150rpm version.

im a huge fan of noctua

Enermax 120mm Magma twister bearing fans has been serving me very well. It's very very quiet without bearing noise (.... or lack of traditional bearing ?), but I can't comment on airflow since I rarely stress my system.