Investing in equipment this day and age is a loss. Almost all forms of equipment are continuously upgraded, and new replacement equipment is put on the market at a monthly rate. Heavy equipment usually takes longer to be outdated, but anything with a technical side, computers, metal detectors, etc... lose value the minute you buy them because there is already a newer better version coming to the market.
Land investments, not sure about your area, sounds like you could sit on land there for quite awhile before it shows a growth in price. Current home, land values all over the US are way down, my house was $230k when I bought it several years ago, the guy down the street from me bought a slightly smaller house a couple years ago but same basic structure for $120k and since he was a first time home buyer the government paid a good portion of that. The question is how long before the house values go back up again? Most likely a few years.
undeveloped land, that is getting harder and harder to buy, and the value is still up higher than I would like to see before I bought, I think the price will still drop on undeveloped land as not very many companies are building at the moment, and those that are pretty much are doing it on credit, credit that they will fall over if the building they are doing doesn't sell.
Gold, silver? I'm not sure I have read reports stating it will still go up, and I have read statements saying it's peaking and will drop as some as some rich guy sitting on a lot of it floods the market again.
Believe in the upcoming Armageddon theories, you might invest in guns and ammo, or preserved foods, and drinking water. Maybe a cabin deep in the woods and a tin foil hat.