It seems to me every fan I purchase only lasts about a year. If this is normal, thats understandable, but do the more pricier fans last longer? First I tried a really cheap brand, those actually still work but the air flow was horrid. Then I went with XG those still work very well as well, but the LEDs died within 6 months. Then I tired Rosewill which seem like the best quality but my 120mm is starting to go sluggish and I have blow on it to help it start spinning "well". What brand is the best quality or does it even matter, and in the long run and they all start to die. Its not that they are expensive, replacing them isn't a hassle I just like to have the best.
Lastly does anyone else feel that larger fans like 250mm aren't adequet? On my case my front intake is 250mm yet on the inside of the chassis the hole for airflow is only 120mm and its dead in the center of the 250mm fan, which on the 250mm it seems airflow is only good along the edges of the fan and not in the center. Same goes with my side intake fan, which is also 250mm, and it seems anything right in the middle of the fan, doesn't get air blown onto it.
I was looking at Thermaltake, the evercool one looks like higher quality but is way to loud.
The main killer of fans is dust build-up. No matter what fans you get, you should regularly clean out your case with canned air. Be sure to blow out the fans, too. I would hold the fan blades still while cleaning them since the air can over-rev them and cause the bearings to fail prematurely.
ThermalTake (TT), Antec, Panflo all make good ones. Panflo are supposed to be some of the best, but I haven't had the pleasure of owning one. I have a 120mm thats been just great. As mentioned Noc also makes good fans, I'm sure there are plenty more.