I also have quite a small selection of rulers but make good use of them all. I've got a 6.5" x 24", a 3" x 18", a 12.5" square, a 6.5" square (my newest ruler to help with the fact that I often work with pretty small pieces) and a 60 degree triangle which I bought to do a stack-and-whack (one block wonder) quilt. So far, the triangle is the only one that's not been used regularly but I am still glad I bought it as I think I'd like to try some more OBW stuff if I ever get my hands on multiple yards of a cool fabric or panel. Like WMU mentioned, I use the diagonal lines on my rulers quite a lot and I would second her advice not to go overboard on buying rulers. Most blocks can be made with basic rulers alone. I've also noticed several people here and in my guild commenting on how many of their rulers get neglected (or put away and "lost") after they have bought them and used them for a single specific project. :-) The more rulers you have, the more you have to find storage space for!