I would add the 8 1/2" by 12" or 24" ruler. Also the Easy Angle rulers. I would definitely add the Creative Grids Stripology ruler. The Stripology ruler is the upgraded version of the June Taylor Shape Cut.

It depends largely, on what type of quilts interest you. I have a BUNCH of rulers but the ones I use the most are my
-June Tailor Shape Cut rulers (I have one in 1/2" increments and another in 1/4" increments) http://www.amazon.com/June-Tailor-Sh.../dp/B000YZ7SJM, to cut strips and/or perfect squares
-two different sized 'square up' rulers, for trimming finished blocks
-small, square rulers with X through the middle, for centering designs
-several long rulers for various tasks
-several small rulers (6") for use at the machine

For the more expensive rulers, check out Hobby Lobby's weekly 40% off coupon.

I have 3 MAIN rulers that I LOVE to use, and they are:

O'Lipfa (they have a lip to help keep them straight on the cutting mats).

Sizes are:

3x18
5x24
4x36

These are the #1 TOP go to rulers that I use in fact I have 3 of the 18"
that I keep near me at all times.

I also have a 6x12 that I use sometimes.

I could not be able to work without my "little" rulers! For me the bigger ones are awkward take up too much room when piecing but great for major cutting.. Favorite - 3 x 9", 2nd favorite - 3 1/2 x 12 1/2.

Thank you, everyone. I am going to have to study these lists and do some research.

If I were you I would add a 6-1/2 " square up ruler. I use it all the time to, of course, square up blocks. I also like my 12-1/2" square up. But use the smaller one more.

I have several rulers, none of them "speciality" rulers, but the 1 ruler I go to, is my June Tailor Shape Cut ruler, there are more than 1 "model", but mine is the one with 1/2" measurements.

I have a LOT of rulers and templates.
The ones I use the most are
6 1/2 x 24
12 (or 12 1/2 I can't remember what it is) square ruler for squaring blocks
5 square ruler for squaring smaller blocks - can do it with the bigger one, but its less cumbersome with the smaller one.
EZ bias binding ruler
binding tool (more of a tool/template I guess but I keep it with my rulers)

I like my 6.5 square . With it i am able to cut smaller squares or pieces at my sit-down ironing center rather stand at the cutting table for everything. I also like my 5" sq. and 2.5 sq. but acquired them (as with each ruler) when I needed it.

being able to read them is super important . I cant have too much jazz on my mine. I like clear ones with thin lines the best.

I think the 12 and a half is a must. The Omnigrip(the green ones) are the best. They really are less likely to slip when you are using them. You can cut most things with just one good ruler like this. A lot of blocks are 12 and a half unfinished, so I would start with this one and buy others when you figure out what you really need or will tend to use most often. I have inherited a few I have yet to use and I don't have a big selection of them.