How about taking some directory that is currently under /var (depending on what you're doing with the machine, maybe log or www or mysql or something?) and moving the contents to /usr/obj or /usr/src (or if they're together on disk, remove /usr/obj and /usr/src and create a new partition covering the space that was used by both)? (Then change the mountpoint in /etc/fstab). If that gives you enough capacity, that might be easier than some big shuffle-around.
That's kinda half-assing it for us, as that would still leave like three partitions around that are 95% empty consuming over a third of the disk. If I'm going to be redoing things, I might as well do it all at once.
