My experience is somewhat different, re. wireless streaming. I haven't been able to stream any music through my PS3 yet, not for lack of trying. Sometimes it will detect the servers, sometimes it won't. It should detect 3 servers (laptop, desktop, Fireball). The desktop and the Fireball are hardwired into the network, but the PS3 often fails to find them. And even if it finds them, I can't play the tracks on them.
I don't know why this is, but safe to say I'm not yet a proponent of the PS3's streaming ability. Maybe my wireless network or router is the problem, I don't know yet, but even the internet is excruciatingly slow, like minutes to load a web page.
I don't see any reason not to load the discs right into the PS3. 3-400 discs will probably use 40g or less?