The quietest fans tend not to be LED lit. I use Noctua NF-A14s, but if you care about looks they're probably not going to be your first choice. There are lots of choices and you should spend some time reading through reviews, but you can get a decent compromise by using 140mm fans (usually more airflow for lower RPMs and less noise than 120mms), getting good quality ones, and running them at lower RPMs.
There are lots of choices but these get good reviews:
Corsair AF140mm Red LED Quiet Edition -
http://www.newegg.com/Product/Product.aspx?Item=9SIA24G28N1393
I would recommend starting with two in the front as intakes and one in the rear as exhaust. If you're not happy with your temps, add another in the top/rear fan mount as an exhaust. You can scale up from there as needed, i.e. 120mm intake in the bottom, but that would be sufficient for most users.