I have very fond memories of Graal. I racked up massive dial up bills and hogged the phone line from my family while playing hundreds and hundreds of hours.

It also introduced me to memory/hex editing. I remember searching for bench.jpg which was located near some players and changing it to cloud.jpg, causing the bench near me to turn into a cloud which then would paralyse my unsuspecting victims. Ahh good times.

Other big MMORPGs for me were Helbreath and Ragnarok Online