It seems 3.1 will drop today, at least by what Zarhym says. Realms are down for extended maintenance, and the devs have communicated on clean-up details like why Equipment Manager won't make 3.1. At this point, it's safe to assume that 3.1 will arrive unless they run into unexpected problems.
Hats off to the guys pushing the build out; I've seen that kind of thing in action and I know it's a lot of work. Here's hoping all goes well.
Assuming it does arrive and all goes well, we'll go through the normal patch dance this afternoon. Log in and start downloading the patch; update as many addons as possible; maybe wait in a queue for the higher-pop realms. Once you're through all that, though, what should you do next?
Manage your specs.
The first thing to do is respec. All your talent points are wiped for this expansion, so you'll need to respec even if you're not taking the dual-spec feature. My recommendation is to build your first spec before buying the dual spec feature. The reason is to make sure you get the right glyphs on the right spec. I logged out as Resto, with full Resto glyphs. So if I messed up and specced Balance first, I'd have to replace those glyphs with Balance glyphs, then buy new Resto glyphs for my other spec.
So, make sure your spec and your glyphs match. Once you've handled that, then you can buy your dual spec if you're so inclined. You'll also of course want to buy glyphs for that spec. I did some shopping last night before I logged out, so I have at least my major glyphs ready to go.
Oh, and if you're curious, I wrote a post about the specs I'm starting with for 3.1.
Once I'm all set with my specs, I plan to begin working my fishing dailies. Unlike the cooking dailies — but like the fishing dailies from Burning Crusade — these will take some travel, so plan for a bit of time because of that. You pick up the quests from Marcia Chase, by the fountain. If you want more details, check out El's Extreme Anglin', which is always your go-to source for fishing information.
When a Wintergrasp battle is close, I plan to get involved with that. The changes to Wintergrasp aren't that extreme, but they should make it just a bit better. My hope is that a few more players will spend time attacking (and defending) the south towers. Remember, you can now capture the south workshops. So if the offense ignores the south as they usually do, you can probably easily capture a workshop, build a vehicle, and start tearing stuff up.
Before or after the fight, I plan to do some Wintergrasp fishing. That will get me more Fish Feast materials, which I always need. It should be easy to find a quiet place to fish; we'll see whether PvPers seek out fisherman.
When I'm done with my fishing daily (and Wintergrasp), I'll head to the Argent Tournament. I suspect this will be the go-to place for running dailies and making money. Plus, it has cool rewards.
Take a gryphon to the Argent Vanguard, then fly north and just a bit west. The Argent Tournament is north of Sindragosa's Fall. You can read a great preview of the Argent Tournament at Banana Shoulders.
So there you go: some good stuff to get started on. Wait, wasn't there some kind of new raid instance too? Hm. That might be worth checking out as well...