Minn-Kota would be my choice for sure! They are awesome. I have two trolling motors (30 and 55 lb. thrust for a 12' and 14' smaller aluminum boat that I fish weekly). My Endura Max 55 flies with the 14' boat, but for your 16' drift boat which is also very heavy, I would recommend a motor of at least 55 pound thrust, possible up to 80 (however over 60 lb. though you need a 24 volt battery or carry two 16s on the boat). Try the Traxxis, Endura Max, or Endura C2 series. I like the Minn-Kota composite shafts because they deflect better off of rocks if by accident you hit one and won't bend like an aluminum one. Motorguide is another popular brand but for the money and the customer service, I say Minn-Kota all the way.
This is the one I have and I also got the trickle charger (5 amp) and it charges the battery great.
http://www.cabelas.com/catalog/product.jsp?productId=1837280&type=product&MDK=dynbanP_DOb&MDC=cat104645880#tabsCollection
I hope this helps! Thanks!