-Somepage-
One of the best resources for information on items. Very complete though missing a few things. If you need to find out how to craft something or where it comes from or the stats on an item this it the place to go. Also has a deal of info on NMs and some minature walkthroughs on some quests.
-MysteryTour-
Very thorough information. This site probably has the most thorough info of any site but it's more difficult to navigate than somepage. There are guides for quests and missions and MysteryTour is almost always the first to get all information updated. Expansion info was being released by the minute after it went live and within hours full info on most new quests and all new job flags was up. Also has good links to some JP H.E.L.M. maps which I find very useful.
-Allakhazam-
Has good armor lists by job and good info on spells/abilities by job as well. Almost all items/areas/mob in the game have their own 'thread' in which people discuss their findings so it's a quasi-wiki though it can also be crawling with misinformation. Alla is notorious for not being caught up. Their info is quite outdated as they have only half of the CoP missions in their database and don't keep up well with items. They have what is probably currently the largest forum system next to KI though many are not happy with Alla as they are now owned by IGE which is the most notorious RMT (Real Money Trade) site.
-Killing Ifrit-
KI probably has the best mission guides on the web. They are a bit easier to follow than those on MysteryTour. They also have a large forum community and of special note is their NM forums where you can find quite a bit of solid information on NMs.
-FFXI Atlas-
Once upon a time it might have been contested that BEB's maps were the best but I think all of the great features that have been added hear make it by far the best map site with overlays of NMs/Coffers/Elementals and such. This is a phenominal map site.
-FFXIclopedia-
This FFXI Wiki is amazing. It's quite detailed though I prefer the layout of Somepage. One of the greatest features is the incredible detail it gives with reference to the Fellowship NPC stuff. Great for when you can't find something or want more details.
-For Glory CoP Guide-
This is without a doubt the most complete and comprehensive guide to CoP there is. If you're working on CoP Missions use this.
-Gates of Aht Urhgan-
This is a newer resource that is giving great and detailed info on all things new in the expansion. It's very similar to the above CoP guide and I'd highly recommend you look it over.
-Koolaid-
This is similar to Blue Gartyr's site... a LS site that has become a resource. It's pretty good but there's nothing you'll find here that you can't find elsewhere in a generally better format. They do have some info that you can't find in other places so they are definitely worth mentioning. If you need to find something and can't find it elsewhere at least give them a try (was great for getting my Uleguerand Range Map)
-Blue Gartyr-
I decided to post directly to the forums as the site doesn't really add anything. If you are endgame and don't wanna see a lot of the more lowbish questions and want to discuss endgame things this it the place to go. Be very very careful though and try not to get worked up (advice I should take) as the locals are none to friendly especially to new posters. Still there is a great deal of good information about endgame things here.
-Dreams in Vana'diel-
This site honestly doesn't offer much more than a forum. It seems in the wake of Alla selling out to IGE a lot of people are posting here. I can't speak much for it as I have not. I do know that a lot of older players post here including people that imported it before it was released NA. From what I do know it is somewhere between Alla and BG and the moderators apparently actually moderate so discussion is kept mature.
That's all for now. I know I've forgotten plenty and will add some later. If you have any suggestions make them and I'll add them to the list for easy finding.
