I have some remote boxes, which are a bunch of Mac Mini's. I access them now through SSH, and it fits my needs to do the maintenance. In the past, I used X11Forwarding with Linux boxes, when I was still using Debian myself, and I was able to run a specific application as if it was natively present (Firefox). I haven't succeeded to do this yet, but I assume because of the BSD underneath the fancy Apple GUI should be able to do such a task similar. I am aware of the remote administration, but I rather keep access limited to SSH on these boxes for inbound connections. I use Leopard myself, so I connect from Mac-to-Mac.
Background information about the why's, tips, advice and comments are all helpful! Thanks!