I would rule out the Olympus because:
- Macro range 3.9" is much more than the Powershot A590IS (2.0")
- xD memory is not really a popular standard (and slower)
- Only 3x zoom
Between the Coolpix P50 and P60, the P60 wins handedly because:
- 5x zoom vs 3.6x (zoom matters to me, and particularly, IMO, for nonSLRs). Whether it's worth the extra 50 bucks up to you
So the choice comes down the A590IS vs P50/60.[list][*] Between the A590IS and the P50, i'd take the canon for the extra zoom and published macro range (dont know the nikon range) -- the extra ISO wont/shouldnt be used anwyays[*] Between the A590IS and the P60, i'd take the P60 for the extra zoom
[l/ist]