I've been promising Altair for a while that I'd post up some of the links I keep referring people to, so finally, here they are! (or at least here are the ones I can remember right now).
Evemon - An awesome program for minitoring your character's skills. Can be used to set skill plans, view skills trained in different areas, and most importantly, tells you when skills are complete/how long until they complete while you're offline!
Eve Fitting Tool - Another essential tool. Just select the ship and fittings you want, and EFT will give you the rundown on your ship's capabilities. Great program.
Ombey's Eve Maps - 2d maps of every region in eve. Include facilities each system offers, as well as number of asteroid belts and whether you can find ice there. Great for planning a trip/looking for a new base, etc, and much easier to understand than the in-game map. Also brilliant for fleet work.
Eve Survival - A great site, the highlight of which is the in-depth description for every combat mission in the game, including what enemies you'll face, what type of damage to tank/deal, which rats will spawn the next wave, etc.
Scrapheap Challenge - forget battleclinic, scraphead challenge is the ultimate site for ship fitting. Want ideas on how to fit out your new ship? This is where to go.
Eve Agents - A complete database of every agent in Eve. Very useful for mission runners.
Eve University Media Archive - A collection of some of the best recorded classes from Eve University, covering topics from Politics to PvP. Some of them are very long, but definitely worth a listen.
Will post more when I think of them.