We seem to have pretty similar tastes and I've also had the same problem recently that some of the artists that I used to follow are hardly releasing anymore or went on hiatus... Here are some random artist that made some songs that I like and a few songs I really like:
Aya Matsuura:
You probably know about her already. She's not really releasing anymore, but I'd recommend all of her singles (A sides and B sides) up untill ki ga tsukeba anata and also that wonderful CM song she did for aoyama after that. =)
MINMI:
Recommending her album "Mother". She's first and foremost a reggae artist, but this album spans quite a few genres and is just really pleasant to listen to.
B'z:
Really like LOOSE album, but also their two most recent studio albums. Here's a clip from their 2009 single ichitozenbu / DIVE
Masami Okui:
mostly the old songs she did for animé Digi Charat, Slayer, revolutionary girl Utena... and also this brilliant party tune: