Planetside has been around for years, and is a MMOFPS. The "persistent" state is the team ownership of different bases/buildings, plus the character skill tree for your character.

I think Planetside had a reasonable skill tree, much along the lines that the original poster suggested, but very shallow -- i e, individual skills within a tree don't typically have a lot of pre-requisites. The main thing I'd improve in their skill system is un-learning; it should be possible to un-learn any skill you have known for at least 18 hours, not just one skill every 18 hours. That way, I can change role once a day, but not in the middle of a battle.

Regarding Planetside terrain, there's an overhead map where you choose the different continents to go to, but you can't circumnavigate the globe. Each continent (island) is probably a single server machine, and thus has a player cap. Back when the game was popular, you'd often get continents that were pop locked, i e the server machine for that continent reached its capacity limit.

Also, I believe there is a free trial of Planetside. If you're building a MMOFPS, you should absolutely download it and try it over a week-end.

[Edited by - hplus0603 on January 26, 2006 12:26:04 PM]

Thank you hplus0603, you've always been a big help! Here this whole time I've been thinking that my biggest competition for the genre had a circumnavigable planet. With that in mind that is what I've been shooting for. My partner and I have been toiling over ways to accomplish this for weeks. We had some crazy methods thought up that probably wouldn't have worked out. We have (for now) settled on a paged grid method that sort of just repeats the grids from the start once you get to the "end."

hplus0603, I know that you shipped a game that allows for circumnavigation on a planet of Earth's size. Any hints regarding the direction I should be going? :)