- Finish Cataclysm Quest Zones: Depending on how you leveled, you probably have one or more Cataclysm zones worth of quests available. If you haven't done Twilight Highlands (and possibly Uldum), there are probably gear upgrades to be had. You might be able to snag rep rewards (and therefore additional gear), along with cash. You might also have the chance to snag tradeskill materials - in particular, enchanters will find a fair number of quest rewards to disenchant.
(Personal Status: My main has about 90% of Hyjal and Twilight Highlands left to do, along with all of Deepholm. It's worth noting that Deepholm has a questline that's an absolute requirement for access to one of the reputations.) - Work on Professions: You can typically expect to level your professions to either 475 or 500 for access to all your self-only perks. Depending on your profession, you may produce gear that you can use during this process. This is another place where Enchanters win, since they get to equip extremely minor upgrades and then disenchant them later for materials.
(Personal Status: 476 Tailoring, need 500 for Embroidery, 486 Enchanting, need 500 for disenchanting max level loot.) - Daily Quests? Surprisingly, there are relatively limited PVE dailies in Cataclysm. There are some in Deepholm, some in Twilight Highlands, and all of two in Uldum. (Hyjal will get new dailies in patch 4.1.) There are also some profession dailies, but the rest of the bunch are specific to Tol Barad.
- PVP: Speaking of TB, you might not be snagging an epic per win anymore, but it's still there and should still be good for some honor. More on this topic when I get around to it.
- Dungeons: Love em or hate em, but it's definitely worth running each instance at least once for guaranteed quest reward loot. You get more Justice Points for accepting the random luck of the draw, but you might prefer to run specific dungeons in search of certain gear. (Also, two of the five random options for level 85's are lower level dungeons that drop inferior loot and, once patch 4.0.6 arrives, markedly worse JP.)
(Personal Status: Have yet to run the three level 85 dungeons. My average ilvl is 320, so I've got a bit to go before I can unlock heroics.)
Should we be playing just for loot?
I get where Spinks is coming from on the gear reset - if we assume that we're going to get a gear wipe sometime around April (plus or minus a few months), that might impact your willingness to grind out all the best stuff. Also, because of automated currency downgrades, individual players can hit a point prior to the patch where it is no longer worth doing random dailies because they will not be able to obtain sufficient numbers of the top tier currency before the patch resets it. For those of us who are planning to spend Feburary 24th through March 30th (or possibly longer) in Telara, it probably makes sense to bank JP and honor to cash in when we get back to Azeroth.
That said, I'm not sure that this is a bad thing, even for Blizzard in the long term. If you're having fun playing, it doesn't matter whether you're still going to be using the same gear in a few months. If the only reason you're playing is to upgrade the arbitrary numbers on your character sheet, then yes, you've got less incentive to stick around. If that's the case, though, I would argue that you're probably not having that much fun. From Blizzard's perspective, it's not worth dragging one last $15 fee out of you if it means that you're hating the game by the time you finally quit and you end up staying away for months or years. In that case, everyone might be just a little better off in the long run if you take a break and come back when there's new stuff to do.