Welterweight by a distance. Superfeather is also pretty good, as are supermiddle and lightheavy. The worst are heavy and lightmiddle.
IMO welterweight is the best. You left out 122 and 115, which I feel are the second and third best divisions.
They governing bodies should sort this problem out once and for all and have a round robin style tournament between the number 1 pound for pound fighters from each division. Who ever comes out on top will have the knowledge that the division they are in is the best.
Cruiser weight is a very hot weight division at present-hotter than supermiddle IMO. top fighters like: Cunningham,Huck,Adamek,Arslan,Tokarev,Mormeck,Haye,Maccarinelli,Wlodarcyk, Drozd,Kraj,Godfrey Tough cookies like:Wilson,Muriqui,Brudov,Hobson,Gurov,Nwodo,Jivor,Cora,Hide Cantatore,Bell, Promising talents like : Flores,Hernandez,Frenkel,Banks,Licina A former amateur star like Solis' old rival Alexeev who campains at cruiser weight.I am absolutely positive that he will soon capture of the orgs' title. Super midde isnt so deep in terms of talent and rising shooting stars IMO.