can somebody tell me which one to buy,I play,christian soft rock,pop,ballad,I am bassically interested in sequencing capability,but would like to compare storage capacity and sound varietty.please help me

for detailed descriptions see
http://www.korg.com/keymod.htm

is40 is arranger keyboard that uses
chords and styles,
n-serie is more midi oriented song sequencer

is40 is easier for live playing and creating songs with automatic accompainment (backing sequences), creating n-series songs is more work

i30 has both variants (song mode, arr mode, backing sequence mode).

Sequencing midi can also be done with software on computer with all of them.

Guenter