What kind of chair is good?

For our back, for general health?  Ideally the chair is not too heavy or huge.  I have wood floor, so I guess the chair should not have wheels otherwise it moves too freely.  Using a mat does not seem a good option since I can trip.
Could you post a picture to illustrate? 
Thanks in advance for your suggestions.

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• Thank you -joeyli- ♀ (19 bytes) () 06/23/2015 postreply 16:27:00