We've enabled mod_deflate on our Apache2 installation. This means that we'll only be sending about 10-20% of the data over the wire for our big fat HTML, JS and CSS files as the data will be GZIP compressed.
If you're considering using Apache2, you must explicitly enable it while building, i.e.:
./configure --enable-mods-shared=most --enable-deflate
Right now, this is what I've added to our config file:
LoadModule deflate_module modules/mod_deflate.so
AddOutputFilterByType DEFLATE text/html text/plain text/xml application/x-javascript text/css
There's probably more mods coming to this yet though.