Also the audio driver ASIO4ALL can be used to reduce delay in input. Dowload here
Continuous Velocity Piano:
One of the best free piano virtual instruments around.
Uses GIGA's Spectral Morphing technology for
greater playability and realism.
Download here
A free versatile virtual guitar amp with many effects such as
overdrive, chorus, delay and many others. Great substitute to
expensive commercial software.
Download here
A guitar effects program with a basic interface with all
common effects such as distort, reverb and chorus.
Download here
A good free virtual piano. Small download size with
some decent features such as sustain and chorus.
Download here
Many more plugins can be found at:
http://www.best-free-vst.com
http://rekkerd.org/fretted-synth