Best bookshelf speakers

Hi all,

I'm looking to buy a pair of good bookshelf speakers and since a lot of you here seems to know about speakers much more then me, I figured I'd ask for advice.

Here are the parameters I'm working with / looking for:

- The room is about 1200 cu/ft
- Looking for great performance at low volume
- Rich timbre
- Rich, warm bass
- Natural highs (not metallic-sounding)
- Low frequency range in around 40Hz (preferably 30Hz, but I know, there are hardly any in this range at my price point)
- $500 - $700, new or used

So far I am considering the following options (in no particular order):

- KEF Q350
- Dali Zensor 3
- Canton Chrono 503.2
- Wharfedale Diamond 225

So my questions are:

1) From my list of 4, which would be your choice?
2) What other bookshelf speaker would you add to the list that fir my parameters?

Any thoughts are appreciated