Sunscreen?

I'm baffled about sunscreens and which one to use.   I've tried these, and I love the way they look: Ti-Silc Sheer SPF 45 by ProCyte and La Roche-Posay 60spf Ultra Light -- I'm trying to wear sunscreen everyday.

But what really concerns me is...am I helping or hurting myself?  All this business about nano-particles, chemical sunscreen, skin cancer, I'm just not sure what sunscreen I should use.  I know should use something after peeling since the sensitive skin needs to be protected, but I'm not sure what. 

In my search for sunscreen information, I found this post on sunscreen technology.  Take a read.  You may end up with more questions than answers, but that's at least a starting point.