I respec'd my rogue alot post-bc trying to find a worthwhile spec since I lvl'd both of them to 60 as subtlety/daggers, but daggers didn't cut it in outland and they made imp sap a normal part of sap too(I rolled the rogues originally JUST to go into enemy towns and piss people off by imp-sappin them...sooooo funny to see them spaz and go apeshit every time they're sapped, aoeing and running around lol); I went around the other trees tweaking constantly to find what worked, mutilate specs, maces, daggers, fists...eventually settled on combat/swords for lvling, then combat/maces for raiding(and it worked quite well; in blues I outdps'd epic'd people and was just shy of the other epic'd rogues of varying specs despite maces being primarily a pvp spec; Trash stun in kara = valuable ass-saver + lets me solo some of the lone caster adds); I've gone back to Subtlety/daggers since then though once they made Shadowstep work in combat and out of stealth and got some daggers worth shit, quite powerful in an experienced rogue's hands ;p

I respec'd my boomkin a few times once I started raiding and a couple times as we progressed based on my survival(or lack thereof) and raid needs sans imp FF, and my Paladin/Hunter have both been through all 3 trees at one point(Pala started holy, then went ret, then went prot - Hunter started heavy BM, then heavy surv, then heavy marksman once they nerfed hunter agi = ap conversions, and now sitting on 21/40/0 lol)...I guess I have mild, rare respecitis rather than chronic versions