So, this week is when I officially switched from selling to buying. This is of course extremely anecdotal and based only on my server (and furthermore, on my minimal playtime), but I get the feeling that now is the appropriate time to bargain hunt in order to get ready for December 7th. I think many of the players that were hanging on to raiding, PvP, etc. a few weeks after 4.0.1 are now in "break mode." We've seen the new talents in action, have a sense for what's coming, and I just don't see as much activity from people buying stuff or even playing. And certainly not the higher margin enchants, gems, etc. that have been my bread and butter. I also think that the pre-expansion bank emptying process is underway, in some regards, so bargains abound.
Timing is everything, and while there's some margin for error, I'll definitely be scouring for the items I mentioned before -- and those listed by many other great blog guides -- to fill up my bank before Cataclysm. Based on looking at some of the blogs on my blogroll, it looks like a few folks out there have been burned by speculative items/rep grinding, so I feel for them but view it as validation (to some small extent) for my pretty boring AH existence.
Anyhow, as far as value items (measured by price-per-slot), abyss crystals are darn cheap right now. Maybe it's people DE'ing their old gear as part of wrapping up this expansion, maybe it's people buying the honor PvP shield and DE'ing it (something I'm not a fan of, by the way). Either way, I bought a ton of crystals at 17g the past few days. It varies, sure, but overall these and other enchanting materials seem to be declining.
Bring it on, I say. Holding onto abyss crystals is virtually no-risk, as you can just shatter them and sell the mats if needed as there will undoubtedly be a sufficient market in Cataclysm. The functional lack of deposit fees is also a reason I love enchanting mats or scrolls. Rare-quality gems have been a time/money sink lately, and I'll likely just cut and vendor the bulk of my piles leftover from the past few months. N.B. the shatter-to-profit point has been made by others, again I'm not trying to plagiarize. It's just an illustration of timing the market to increase future earnings. Buy low, sell high, right?
As an aside, I've been working on leveling a shaman and really love it. I actually enjoy healing more on the shaman than my paladin at the moment. My shaman, by sheer coincidence, is also on the server of another respected gold blogger, so it's fun to watch an expert in action from the sidelines. Still, it's all time-killing until I dust off the pally in December.