I like the Fine Line rulers from Accents in Design. Web site is
http://www.accentsindesign.com/
The rulers "stay" better than any others I've tried, but everyone has their favorites!
For curved quilting, I use Ronda's Mini, which can be found here:
http://www.quiltersrule.com/template...sRulersFP.html
I've found this one works best for me in most circumstances - I can use it to follow some curves as well as to keep my hand steady for others.