Upgrade the clients. 100Mbps is fine for clients but have a gigabit
uplink to server.
That depends on what is meant by "upgrade the clients." If you mean
"add some DRAM to the existing clients," then I'd agree, 'cause
there's nothing wrong with those clients. A few years back, 32MB in
the clients was enough, but now I typically put 256MB in mine 'cause
of the way Firefox does image caching in X11. I still have a
Pentium-166 MMX and some AMD K6-2's from 10-12 years ago, and they
work great. They have 100Mbps cards, and they have decent video
boards (Matrox Millenium G400, ATI Radeon 7500, etc.).
+1 on the "upgrade the *server* to Gigabit" suggestion.