I am painting a knight and would like to konw what paint is best for reproducing armour, I would prefer acrylic but any suggestion will do.

Testors Metalizers work well IMHO, but if you want something that REALLY buffs out to a bright shine Alclad II Lacquer is the trick. Alclad is a little touchier to work with 1. You need to primer first with either "Plastic primer, Future, or Auto primer" quote from label. 2. You can only use Lacquer Thinner with it no Mineral Spirits. 3. and of course you can only spray apply it. 4. A little expensive $7.50(US) for a 1 oz bottle. Comes in all kinds of flavors Copper, Aluminum, Steel, Gold. Should be available at any good Hobby shop.
http://www.alclad2.com/index2.html

I use Model Master Metalizers and also Humbrol Metal Cote. Of both I prefer MM.
I herad about the Alclad II to be very good, but I didn´t try it.
I feel comfortable using Model Master. Right now I´m building an F 84G Thunderjet (Tamiya) in 1/48 and I will use them (diferent shades). When finished I´ll post some pics.