List of music stores in...

Sydney:

Pro Audio:
Sound Devices - CBD (Fostex, Genelecs, others on the shelf)
Allans Music - CBD and Alexandria (more PA than great synth and monitor selection)
Intermusic - Bondi Junction (Focals, Mackies, maybe Tannoys on the shelf)
Turrumurra Music - Turrumurra
Billy Hydes - Camperdown

Synths:
Intermusic - Bondi Junction
Hutchings Keyboards - Bondi Junction/Bellevue Hill
Sound Devices - CBD

Guitars:
Intermusic - Bondi Junction (they have some cool boutique pedals, but mostly it's a fairly run of the mill Ibanez and Fender affair)
Allans - CBD, Alexandria
Billy Hydes - Camperdown
Guitar Factory - Annandale
Bass People - Annandale (Used to be The Bass Player... Not quite as cool anymore, but still lots of basses)
Jackson's Rare Guitars - Annandale (Got too much money buddy? You can buy your pre-war Martin here for $30K.)
Global Vintage - Annandale (these guys sell lots of cool guitar gear ... heaps of secondhand vintage shit, boutique pedals and heaps of Japanese imports - I haven't been since they moved from the city three years ago, though)
?? - Redfern (I know there's a shop - I think it's on Botany Rd)

In general, if you're looking for guitars, it's worth heading to Parramatta Rd, Annandale - there's a strip of about eight guitar shops.

DJ Gear
DJ Warehouse - Petersham
Lightsounds - Darlinghurst and Petersham
Spank! Records - Darlinghurst
Store DJ - Darlinghurst