Vectan powders are always popular as they seem to be much cheaper than the powders from the US
http://www.nobelsport.it/public/page...8&FamigliaID=0
Aliant Powders:-
http://www.alliantpowder.com/reloaders/index.aspx
Hodgson Powders:-
http://www.loaddata.com/members/list...ugeid=4&type=1
Personaly I'm using Alliant Green Dot for my 12g Slug loads.
It depends what you are shooting (clays or high Pigeon etc?) & what powders are available in your local RFD's
I'm sure there will be some more knowledgable bods along soon but the above links should give you something to browse while you wait