Best way to combine file systems?

[Ross Boylan <RossBoylan@stanfordalumni.org>]

My partitions are filling up and I need to start juggling parts of my
filesystem.  Although some of one disk is under a volume manager (LVM
via EVMS), I don't want to fiddle with it.  Mostly this is because I
don't want to extend the container to include a second disk, thereby
doubling my chances of disaster and forcing me to keep the disks
together. 

So I think my two choices are using symbolic links are mounting parts
of the filesystem at other points (I have a 2.4.21 kernel; mount
--rbind looks like what I need).

First, my impression is that mounting is preferable to using symlinks
because find, tar, and others ordinarily do not follow the links.  In
some cases they have options to change that, but this screws up
handling of my "real" symlinks and also invites me to forget the
option and just miss part of my filesystem.

Do people agree that mount --rbind is generally preferable?  (I think
this is a well known system administration issue, but googling didn't
turn up much).

Second, if I do that, is it possible to set up these mounts via fstab?
How?  And if it is possible, is it a good idea?

Thanks.