You said triangle strips, which concerns me. Read this first:
I want to draw lots of NxN grids from triangles. ....using drawElements, triangle strips, static draw.
See the bit by Forsyth and Castano on optimizing for regular meshes. If you happened to know exactly how big the cache is, yeah you could chose your stripe width if you're just going to walk back and forth with constant width. But you don't know this, unless you do iterative microbenching to look for performance falloffs (or code your own vertex shader cache in a GLSL compute shader/OpenCL/CUDA). So you want to pick a conservative size to optimize for, or just use an algorithm that performs well across a range of vertex cache sizes like Forsyth's.
I want to draw lots of NxN grids from triangles. ....using drawElements, triangle strips, static draw. I guess within a grid after every row I should change the direction of the draw(so after a left-to-right row I do a right-to-left row) so I get more cache hits. ....and I would like to know whats the "ideal" N number for this?