$99 must be a magic price point…at least for me. When I see that a plug-in that I took a pass on has been reduced to this price I take notice and reconsider it in light of the new price. If the value proposition changes because of this new price, I might at that point pick it up.
There seems to be a lot of these markdowns floating around. Must be that whole end-of-year sale thing + the recent downturn in the economy + time for new versions to appear. Whatever. There are some decent deals to be had this month.

Now at a smashing new price...
Case in point: Guitar Center is selling Arturia Analog Factory for $99. This is a decent VI featuring either 2000 or 3500 (depending on the version) analog synthesizers sounds selected from the Arturia Classic Synths (Minimoog V, Moog Modular V, CS-80V, ARP 2600 V, Prophet V, Prophet VS and Jupiter-8V). With the 10% off coupon in their recent flyer, the price is $89.10 so I picked one up. Note that the GC advert seems to refer to version 1.0 of the plug-in but when I went in the store they handed me the newest 2.0 version.
GC also has several of the Uberschall Liquid Series on sale for $99 as well. (However, even at the $99 price, I’m still not interested.) Other VIs are also on sale. I also noticed some really interesting in-store prices on project studio monitors like the Yamaha HS-50M, KRK Rockit 5 G2. I don’t think these were advertised in the recent flyer.
Another good deal (and not from GC): If you buy Rob Pappen’s Blue for £199/$239, you get Albino 3 for free. That effectively makes the price of these two great VIs $119 each. (Ok, it’s more than $99 each but it’s still pretty sweet.)