Certicards have been my primary. Not as rough as cast bars but don't have coin premium's. Best of both worlds IMO.
Bangs for the buck, same with silver. Mostly bars but some coins as well, austrian phils, maples etc but no numis. (not that no numis at all, tho i wouldnt buy them for investment purpose, just have for their looks)
I'm currently all coins - but if I was starting over I would probably place more emphasis on bars. Used to have a number of 1/2oz, 1oz and 2.5oz cast bars - they're neat. I know some people are only stacking 50g Certicards.
1 oz gold lunars straight from PM or pre allocated with no premium.... when available....i have been trying to buy the mouse, ox & tiger x 2 for a while now for a friend with no luck, happy to pay good premium but no sellers here or ebay. Seems to be the way to go for me and offers a little down side protection or buffer. 200 gold coins are great with the stop loss feature built in....less so now since the rise in the POG but in a selloff offer great value
When the 10 kg lunars are not available then 1kg lunars will have to suffice. [imgz=http://forums.silverstackers.com/uploads/4435_10kg_gold_dargon-press.jpg][/imgz] Source: Perth Mint Source: http://www.flickr.com/photos/lawrence_chard/6315358118/ In the real world 1 oz lunars, eagles and pandas
Gold sovereigns, all the benefits of minted over poured, recognised world wide, very liquid, none of the ridiculous premiums associated with the Perth Mint, minor collector status for ones in good nick. I can afford to buy one every couple of paydays. They have a dragon on them!