Here's a good independent evaluation of insect repellents.  There are many bogus reports and testimonials about what works to keep mosquitoes away--but get the facts.  Citronella and "Skin So Soft" have many unsubstantiated claims, but anything works in town where there are essentially no mosquitoes!  Even water works until it dries up.

What insect repellent do I use?  NONE.  None whatsoever!  That's right, and I haven't used any in almost 20 years!  But think about it.  Whatever organic compounds we put on the outside of our body get absorbed through our skin.  I'm out hiking almost every day, from early May until mid September.  If I used an insect repellent every day, I'd be taking in so much of the toxin that I'd probably be dead or at least half crazy before the end of one summer.

It's not that mosquitoes don't like me.  On the contrary, I'm probably one of their favorite bloody targets.  And I'm usually wearing just shorts and a short sleeved t-shirt.  But they rarely get a taste of me, even when they're really thick.  My defense?  I carry just a headnet!  But get one that's black.  No, not green, not white, not even clear!  BLACK.  Why?  It doesn't reflect as well in sunlight, so is much easier to see through than any of the other colors.