Assuming you want a new one, for value for money it has to be CZ @ £250. If you want the best you can buy for twice the price go for a HW60 J.
As for shooting fox with it, it is against Home Office Guidelines (not against the law). You must be very accurate with your shot placement, and I wouldn't recomend it. To quote DEFRA on the subject "It is the calibre of the man that is important, not the calibre of the gun." Humane kills are a must, and you would be better off using a centrefire.
Ammo for bunnies: Winchester or Eley subsonics. When used with a decent sound mod (e.g. Parker Hale £30