As someone said, fury and arms are good for different things. A warrior 100% dedicated to dps'ing in raids should probably have both a fury and an arms spec and switch accordingly between boss fights (and trash).
Generally fury is much better than arms if there's a good supply of adds to be killed. For instance on freya, thorim, and yogg final phase in ulduar... A fury warrior specced into improved cleave and cleave glyph just do sick DPS there. If an add phase lasts longer than bladestorm's duration, go fury.
Furthermore fury has the best "burst on demand" with deathwish and recklessness. Many fights have a nuke phase which require you to do a truckload of damage in a short duration of time to a single target... I'd say fury warriors are among the best for that (bladestorm is pretty meh on a single target, at least compared to fury's cooldowns). If there's a short burnphase with multiple targets, arms will probably come out on top.
For simple tank'n'spanks, arms might be better when the stars are alligned, but overall I certainly prefer fury (in ulduar gear).
Finally an important point is how fury seem to scale so much better than arms with raid buffs. If you're in a raid without proper raid buffs, arms will do way more dps than fury - unless you can spam cleave on multiple mobs 24/7. So basically in 10mans you are probably better off as arms... but many 25man raids have crap raidbuffs as well.
A good tip is to always be aware about what buffs your raid are supplying for you... I got addons telling me what I get so I can whine accordingly
... WF (or imp. icy talons from frost DKs) is without a doubt the most important buff for a fury warrior... If you don't get it, you just do crap dps. It's not that big of a buff for an arms warrior though. (personally I do like 1000 dps more as arms than fury when dps'ing selfbuffed only on training dummies... while in properly buffed raids I do at least 1000 more dps as fury than arms).
But yeah, learn to love landsoul's spreadsheet!
My personal experience is that it's very accurate.