I\'m working with a huge table which has 250+ million rows. The schema is simple.
CREATE TABLE MyTable (
id BIGINT PRIMARY KEY AUTO_INCREMENT,
You didn't mention what your workload is like, but if there are not too many reads or you have enough main-memory, another option is to use a write-optimized backend for MySQL, instead of innodb. Tokutek claims 18x faster inserts and a much more flat performance curve as the dataset grows.
tokutek.com
http://tokutek.com/downloads/tokudb-performance-brief.pdf