I would say it depends on how many. Here I have about 60 Skolelinux
computers to manage. A few years ago they were almost all thin
clients. Today they are almost all normal workstations (not diskless).
I don't have the budget for good servers or fast network gear, so I
avoid performance bottlenecks if I use ordinary workstations. Anything
with 512MB (but better with more) works with LXDE on Squeeze.
I keep Clonezilla images, which I update occasionally. I know I am
wasting the advantages of ltsp, but performance is just not acceptable
anymore, even with diskless workstations (with my hardware)
Obviously if you have hundreds of machines, you will not try this.