Tokyo, Singapore

Hi all, I moved to Tokyo a few months ago, and I'm still looking for a good record store. I could find lots of interesting stuff in Tower, Disk Union and other big chain stores; however I'm looking for places more like Other Music, Aquarius, DMG, etc. I'm especially interested into vinyl. Any advice? I'm also going to Singapore for a few days, I think records will be cheaper there, so pointers about this place are also welcome. Thanks in advance -- Julien