My favorites are made by Creative Grid. The lines are clear, but not thick.
I have an Omni Grip that will be going w/ me to the guild swap table - I HATE all of those lines all over. The neon grippy things make it impossible to see the measurement lines on the fabric edge. Luckily, it was a gift so cost me nothing.
I started w/a 6 X 24 Fiskars (which was okay; don't even know if they make them any more) and slowly built my collection. My most used now is a 6.5 X 12. I even cut my strips with it (fold fabric 2x). I also use my square rulers a lot - I like to square everything up as I go - and have them in many sizes from 2.5" to 15.5". The only "speciality" ruler I have is a QIAD flying geese one, I do like that when I am making geese.
Bonnie Hunt recommends an Easy Angle; I haven't tried one yet. I'm starting to get my scraps into order using her system, so maybe soon I'll try the ruler.