I usually put in 25-30 miles a week and I've found that ASICS are the best!  I have a really high arch and need good support and lots of cushioning.  I can always tell when my shoes are getting to the end of their support because my feet will start hurting even though the shoes may still look new.  Some shoes will only last 3 months but ASICS usually last 4-6 months.  They are worth the price to keep my feet happy!