I have to agree with TGBlank... Nothing in the game even comes close to the financial Philosophers Stone that is the Display Table XL (8 slot version). Collecting rocks & gems is vastly more profitable than one would imagine, ESPECIALLY when you are collecting in the World Adventure areas. Al Simhara has the copper mines on the island (all you are looking for is quantity), France has so many titanium ores lying around, you can spend the entire day and never collect them all. China is not the best due to it's very unforgiving layout, but there are several areas that are good places to collect.
In Sunset Valley, the nodes are horribly far apart by comparison. I don't play Riverside much, so I am unable to comment as thoroughly as the other areas, although Simhenge is almost always a solid place to scout out due to the heavy node load nearby.
Using your maximum travel privileges, it is very easy to max out your money (A little over 2 Billion simoleans) inside of 60 days. Just take trips as quickly as possible and collect every waking moment you are able. --- Usually this takes about 40 to 50 combines once you have a compendium bar worth 50,000 - I make a supernovium bar to start things out right.
>>> I have tried Metro's guitar hero method and aside from taking care of the absolute needs (food-energy-bladder) I was unable to get past about 700 performances cancelled before I gave up out of boredom. If you can get past 1000 performances cancelled, you have to be a machine. Even then I couldn't get close to Metro's results, so I will say he is the owner of the guitar ATM machine.