I thought I’d update my post from ages ago about interactive army painters.
Bolter & Chainsword has an amazing set of interactive army painters available, letting you plan out a general look and feel for models before you try them. Its no substitute for trying a model or two, but does let you think about your colour choices!
The best painter is for Space Marines, unsurprisingly
There is another one for Terminators.
and for the Sisters of Battle.
You also have Chaos Marines.
The Tau – Fire Warriors.
There is a painter program that handles both tau and eldar – its simple to use, but not as flexible as the Bolter and Chainsword options here.
Although its a little over complex and fluffy, there is a great Tyranid painter program here
Haven’t been able to find any for Imperial Guard, Dark Eldar, or Necrons though. One suggestion is to use the Dawn of War army designer, and take a screenshot of the outcome.