Need to wrestle a large PDF (i.e. from TeX) with lots of images? Ghostscript is your friend! -dPDFSETTINGS=/printer seems to give good results with a perfectly legible PDF.
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/printer -dNOPAUSE -dQUIET -dBATCH -sOutputFile=small.pdf big.pdf
http://tex.stackexchange.com/questions/14429/pdftex-reduce-pdf-size-reduce-image-quality/41273#41273
