Seems like a decently not too noisy-ish system..
However, depending on how severe your case of 'the silence bug' is, you might be astounded how much more silent it can become!
I thought I was 'ok' with the noise of my old PC, with a 12v 80mm (3000 rpm) PSU fan and a 4500rpm 60mm taisol fan on the CPU. Then I put bigger, lower speed fans in the same system. Wow.. However, somehow... ... need.... less.. noise... must... be... even .. more.. silent (etc)
Then temperature probes came, HD suspension happened, heatsinks got better, Fans got slower, and after the first 'wow' I'm another 'wow' factor further..
You could say that when you're happy with the noise levels, the situation is 'ok' and there is no need for further silencing.. However, once you've experienced a far more silent system, perhaps you'd re-evaluate your views on how happy you are with the first attempt.
I do think that with some of us here (including me for sure!) noise tends to get a bit too much of an obsession. I could barely hear the computer and could easily sleep next to it. After that, the few dba I won where more 'wasted time and money' than real functional value.
In that respect its probably good to draw the line somewhere, but still its good human nature to be curious on how things are beyond that line..