A 6.5 "x 24" and 6.5" x 12" are a good starting point. If you are good at maths you should be able to work from these two. Once you advance you may decide to buy others but remember rulers are expensive and buying a ruler to make one quilt isn't very economical.
BTW Welcome to the board and happy quilting.

Most of my rulers are Creative Grids. I like the thin lines. makes measuring easy. My most used ones are 6.5" x 24.5", 6.5" square, 6.5" x 12.5". There are others in my collection, but they were bought for specific projects and aren't used much.

I agree on the June Taylor shape cut ruler especially when you start cutting lots of strips. It's indispensable. And I'd start with and stay with the Creative Grids. They're the best rulers out there.

What do you use to cut the strips with the June Taylor shape cut ruler? My 45mm rotary cutter doesn't seem to fit the grooves.

I have a 5x25 Olipfa that I use for cutting most of my strips. It has a lip at one end that fits nicely against the edge of the mat and helps anchor the ruler to prevent slippage. I also love my 6.5, 9.5 12.6 and 15.5 inch square Creative Grids rulers.

I use my 45 mm rotary cutter. It should fit just fine. Are you starting it in the teardrop shaped opening?

I am taking notes on these rulers and researching the price of them all, just in case I should come across a good deal at the Houston show! It's getting so close I am jumping inside my skin. My 1st quilt show and some cash from DH! I'll be running...well not running but going as fast as my handicap will let me to see everything I can see. And with some luck I'll get some good deals, I don't know a lot about everything but hopefully I wont get ripped off on a price that I unknowingly think is good. On a side note I am getting soooo close to getting my new sewing room remodeled that I can taste it. The painter came today to work up a price for repairing cracks in wall from house leveling and the whole painting job, then DH will be laying inexpensive flooring. Then the great part of moving all 10 machines & tables in here & sewing my little heart out! Can you tell I'm excited as all get out!! By Dec 1st the room should be done & things moved in!! Hooray for this Momma/Gammy.

I use both my 45mm and my 60mm with no problem - I just grab the nearest one. Mine are Fiskars. You do have to make sure the blade is touching the mat though, so sometimes you may need to give a little 'wiggle' to make sure it is.

I, too, have a 24" ruler that is my "go to", but it'w 5" wide. It sure came in handy when I was cutting 2.5" squares for the swap! I needed 15 squares of each fabric so I cut four 5" squares, then sub-cut each of these into fourths and had a square left over for myself!

I also have a 9.5" and 12.5" squares that I use a lot for squaring up blocks. I have a few specialty ones, too, such as Easy Angle and Companion Angle and Flying Geese, etc.

One that hasn't been mentioned that I love is my little 1" X 6" by Omnigrid. I have several of these (well, 4) and use them all the time. They are great for checking seam allowances, patch sizes (oh, that's why this block isn't fitting!), etc . I have one at the ironing board, one in my little notions basket next to my machine, one at the cutting table, and an extra. So handy!