..and do not forget that Terminal Server does not have the ability
to use what Citrix calls "Pulblished Applications". Published apps
are way cool in addition to all the features that were already pointed
out be another post.

Published Apps, to me, are where it's at. I do not want to load/look
at a whole desktop, nor do I want my users to have that either.
At my last place I had a Metaframe server that I put in, it was
certainly a joy and a life saver. I had my trusty Debian/Apache
box running my Intranet and all I did was publish all the App's
right on the web page. One-stop shop for everyone.

I could be wrong, but I believe LTSP is along the same lines
as Terminal Server in that it too does not have any
ability to create/utilize "Published Apps".

Citrix also has some very fine client software management.

just my 2 cents as well

v/r
-Mike