Well the bands I listen to are a mix of contemporary and older Jrock groups, although I rarely listen to visual Kei stuff, too much flash and no enough substance in my opinion.
My favorite groups are as follows:
The Alfee, quite possibly one of the longest running bands in the scene today
T.M. Revolution/Abingdon Boys School, He's just fun to listen to.
The Pillows, Face it everyone loves The Pillows.
Asian Kung-Fu Generation, another fun group to listen to.
Psychic Lover, They mostly do OPs and EDs for shows but they will be stuck in your head for weeks.
And lastly but my all time favorite
JAM Project, If you want music to make your life seem more exciting just by listening to it, then JAM Project is your group.