Currently the poll says this...

BearShare 23.08%
LimeWire 30.77%
Gnucleus 23.08%
MyNapster 0%
Gnotella 7.69%
Phex 15.38%

This is out of a measly 13 votes... in real world experience from running my own gnutella client (I run phex)... out of 101 unique IP address clients that connect to download from me...

BearShare 42 (41.6%)
LimeWire 40 (39.6%)
Gnotella 15 (14.9%)
Gnucleus 3 (3%)
Phex 1 (1%)

Of course these are people downloading from me, and are partly skewed by the files I provide.