Of the four options in the Tracker, I'd go to the 4" Titanium Tracker, and with the .357 as the pick thereof, with second-place being a toss up between the .44 and .41, with the .44 probably slightly ahead simply for the .44 Special capabilities.

The Titanium is just THAT much lighter, and corrosion-proof, not just resistant. 7-shots in .357 beat 5 in the .4 magnums, IMHO, and I'll go with that... and probably will.