Eve is good but you have to remember that there are no actual "player characters" in Eve, just big monster ships so that works well for them.
UO has the right idea with their "what you work on is what you gain in" system though I think it should also "tree" out more physically besides being able to make certain items after so many points. This would allow players to become more specialized creating better items while giving everyone a niche.
As it stands right now, there are just too many crafters in UO. Not many people are able to actually make a living selling just crafts since 'EVERYONE" has a GM in almost everything.
EQ has a similar system of skill gain but its just way too hard to gain. If you make an item under their new skill system, it is pretty damn nice though and sells off vendors.
Other games like Star Whores and Anarchy Onlamers have a system that uses levels and allows you to buy so many points each level worth of "any" skill based off your race/class. Personally I don't like it...I feel that if your sitting at the bank making studded leather cod plates then that should be the only skill you gain in besides maybe "Gossip" or "Testing my patience".
Britain is currently under attack in the real UO and a person actually came to Skara and asked a friend and I "Where is the new bank parking spot".... I was playing my Dread and responded..."I don't know, we're not sheep". Seems *flocking* together in front of the bank with 200 stones of crap hanging off you is all thats left for UO players to do.
Yes I know that its way in almost any game, EQ is even worse. Perhaps in the games where people say the servers are devoid of life, they just haven't found the correct "Bank parking spot" yet. Thank you E-Gay for destroying every game on the face of the planet and turning every game into a "let's see who's the richest dumbass" festival...
So the short answer to the question is... (

) I think a combination of the system used in UO and Star Whores. "What you work on is what you gain in" combined with a "skill tree" that allows the players to make some killer items such as houses and ships.
Dev (the digresser)