A basic decision tree for what I do when I sign into WoW:
A) Is Wintergrasp starting up in the next few minutes?
A1: If I haven't done the dailies yet, go to Wintergrasp.
A2: If I HAVE done the dailies, but the Alliance will be attacking, go to Wintergrasp anyway, since the win is worth more.
A3: If the Alliance is on defense and I've done the dailies, it's not worth braving the lag. Skip to C.
B) What do I do when the Alliance owns Wintergrasp?
B1: Have I done Archavon yet for the week? If so, LFG for Vault-25, followed by Vault-10.
B2: LFG for heroics. Currently, this list is Culling of Stratholme and The Oculus, the last two I need for Northrend Dungeon Hero, and Azjol-Nerub on the off chance that the wand drops. I'll consider other options such as the Heroic daily if they sound like a good deal in terms of badges, shards, etc.
C) What do I do if the Alliance does NOT own Wintergrasp?
Now would be a good time to go after achievements, quests, and other things that aren't dependent on who owns Wintergrasp. I could do instances in this time - and perhaps I will if I'm looking to get a particular dungeon in and won't be on until the Alliance can get Wintergrasp back, but it's not my first choice. I'd be doing just as much work as when the Alliance owns Wintergrasp, but getting fewer rewards for doing it due to the lack of shard buff.
The schedule isn't completely in-flexible. I'll put other things on hold if there's a guild group forming up. Time-limited seasonal content jumps to the top of the list. Still, it's remarkable how one addition to the expansion has the effect of structuring a large chunk of previously unstructured time.
Death From Above Addendum
I'm not typically one to go seek out PVP when there aren't lots of battle rewards dangling in front of my nose, but I made a bit of an exception this evening after falling a single kill short of completing the daily quest for kills in Wintergrasp. I've fallen 2-3 shy before and let it slide, but a single solitary kill seemed too trivial to leave the quest uncompleted for the day. So, I rode out to the tower above the area where the eternal fire elementals live, threw on all my buffs, cast slow fall, and dropped in to rain icy death on some unsuspecting warrior, just quickly enough to cast invisibility and flee before his fellow fire farmers noticed that there was an enemy player in their midst. (Or maybe they appreciated someone slaughtering the competition?)
My apologies to the random warrior I ganked - it's a PVP flagged zone, with better drops than can be found outside for a reason, and it turns out that even a carebear like myself will, in fact, kill you for the right incentive (1.2K honor and 3 shards in this case).