Some other things I might mention that could help your system out a little. Disable group
cpu scheduler options in kernel, and you might also try using the deadline scheduler for I/O instead of the default CFQ. Gives me a little better "feel" set up this way. File transfers from one drive to another are a little better but the same when going same drive.
I don't how many apps you compile from source, but I have found gcc 4.3 and 4.4 to be noticeably slower than GCC 4.2 compiling and the resulting code isn't any faster either. Took a little bit of time to get that one straightened out.