http://www.pcworld.com/businesscenter/article/245856/chrome_...
Summary:
* Study (commisioned by GOOG but methodology is open for inspection) puts them #1 out of 3 (being IE and Firefox)
* Patched faster and more often than others
* Untouched at least year's pwn2own
Edit: Oddly enough, this was the #1 result for "chrome most secure browser" on Google. One should really do a cursory search before throwing the citation flag.