Get the lowest cost NON plastic.
Solid-brass bodies last longest and require the least care, especially with hard water, which corrodes lesser metals. At $150 or so to start, these faucets also cost the most. If you aren't sure whether a fitting is solid brass, pick it up. It should feel heavier than other units. Often, the box will read "all-brass body" versus "ZMACK" for brass- or chrome-plated fittings. Faucets with die-cast zinc-alloy bodies cost less (typically starting at about $70) and deliver good durability. Zinc is the metal beneath most brass- and chrome-plated fittings. Because zinc corrodes when it contacts water, these faucets must be replaced when the plating wears off. Stay away from low-end faucets with plastic bodies. Though their $50 entry price might be appealing, plastic simply doesn't hold up.
http://www.thisoldhouse.com/toh/article/0,,214006,00.html