First I聮d recommend you visit a running-shoe specialty store where a fit expert can take a look at your stride and determine if you overpronate or supinate. Then, I聮d try on every shoe in the store that suits your anatomy to compare and contrast the fit.
If you happen to have a narrow foot with a high arch and a relatively neutral running gait like mine, I聮d recommend either the Asics Gel DS Trainer 14 ($110; ) or the Adidas adiZero Aegis ($110; ).
The Gel DS Trainer 14 is Asics聮s most popular shoe among triathletes. It聮s lightweight and agile, but has a structured outsole that provides ample support and cushioning. At 8.6 ounces, it聮s not as lightweight as a racing flat, but it聮s super durable. I聮m not training for a triathlon, but I聮ve been logging miles in the Gel DS Trainer 14 all summer, and the air mesh upper and the gel technology have held up beautifully, despite the fact that my regular 5-7 mile route is a mix of pavement and dirt.
Adidas AdiZero Aegis is the same weight, 8.6 ounces, as the Gel DS Trainer 14, but it feels lighter and more minimalist on my foot. Built as a lightweight, high-performance stability shoe, the AdiZero Aegis is designed for smoother and more natural touchdowns at high speeds and will no doubt do the trick during triathlons. If you聮re not a wuss, like me, who needs a lot of extra cush, this might be the shoe for you.