I use OFF, with friends having caught West Nile in Texas I will take the chemical blocking. According to reports I have read under 30% DEET is considered safe both for humans and by the EPA.

I use OFF Active:
9 oz. aerosol (15% DEET, mosquito protection for up to 6 hours)

There is the Family Care that has a DEET alternative:
OFF!® FamilyCare Insect Repellent II Clean Feel

Contains Picaridin (an alternative to DEET) to provide repellent protection without the greasy feel. It is virtually odorless, so it's perfect for social gatherings.

* Pump-spray (5% Picaridin)

This is what I found on Picardin at greenerchoices.com:
Picaridin is a chemical repellent that’s considered as effective as deet at the same concentration by the Centers for Disease Control and Prevention (CDC). When used properly, it’s also considered safe by the Environmental Protection Agency (EPA). Our tests found that Cutter Advanced Sport with 15 percent picaridin scored better than two repellents with 7 percent deet. It protected against both mosquito species for an average of almost 3 hours and against ticks for 11 to 12 hours.

The Greener Choices website has suggestions if you don't want to use bug spray.