Nothing too great or too bad about Cat's Music. They're on River's Avenue where the old Harbour Records & Tapes used to be (remember records? remember tapes?).
Pretty generic selection of music. Don't go here if you want something that's relatively obscure or old. Definitely no out-of-print music here. Sometimes have a decent selection of imports and boxed sets, sometimes not. If you want really good music and a really good music store, go for something a bit more independent like Manifest