Depends on what you want to spend.
If money isn't an issue, I really like the Lightstream 4-14x44 FFP scopes (I have two; on my best HW-K's).
Optics are excellent (compare to a £200 scope and you can easily see the difference) and the FFP mildot ret means that you can change magnification and be guaranteed not to lose zero. Aiming points (mildot reticule) remain the same on all magnifications, unlike most scopes, where the aiming points only work for one magnification (e.g. the SR6).
For example, with a FFP ret on a .177, 15yds is bang-on zero, on any magnification.
20-30yds requires holding the crosshairs half a dot below target on any mag.
35yds is always bang on zero on any mag.
40yds is always half a dot holdover.
45yds is always one dot holdover.