Some games have amazing wiki sites or one centralized fansite that makes finding information easy.  It's a bit harder for Lotro.  Here are the sites I refer to regularly.

Where Am I?
Dynamic Maps of Middle Earth: full maps of whole regions with quest items and npc's marked. The link takes you to the Shire; simply use the dropdown menu to explore other regions.
Regional Maps: On this excellent blog, select "Guides: Zones" to get great full maps with points of interest identified in a handy chart.
List of Travels and Swift Travels: Want to know whether you can get from here to there? Check out this list.
Barrow-Downs Breakdown: Specifies which barrow is which and what can be found inside.

What shall I do?
Quests: A full listing of all the quests in LoTRO.  This site doesn't provide walkthroughs, but basic info is available for each.
Tasks: A listing of tasks by area that includes info like how many items are needed and whether the task gives reputation and with whom. Very useful for determining whether an item is vendor trash.
Virtues: Calculate the effects of different combinations and ranks of virtues and search for deeds with virtue-rewards by zone or virtue.
Deeds: Select the zone and specific deed to find a map indicating where to head in order to complete it.
Go Fishing: Info on fish, fishing, and related NPC's.

What shall I wear?
Darzil's LoRTO Outfits: a pictorial database of all crafted and purchasable armour, outfits, jewelry, cloaks, etc. Stats are given for equipment. You will be amazed at how much info there is available here.
For inspirational outfits check out these blogs:
     Cosmetic Lotro        Lotro Stylist           Lotro Fashion

How shall I decorate?
Housing Items: Invaluable resource showing you what every decoration, floor, and wall looks like; floors and walls are also shown in every paint available

Which shall I ride?
Steeds of Middle Earth: Pictorial list of all the horses and goats available

Quenya-English Dictionary: the high Elvish language
Sindarin-English Dictionary: good for making authentic names for elves and men of  Gondor
Old Norse Naming: good for making authentic names for dwarves and men of Dale