As a bit of follow-up, there was a bit of confusion when the updated sound libraries were released, but I think it was resolved . . .
However, as note in my first reply, I recall that there are some instruments included in the updated sound libraries that do not come with Notion 3, and those instruments only will work if you purchased the corresponding add-on instrument library . . .
However, the updates to the Notion 3 sounds will work, but I think that you have to install them one at a time or whatever . . .
I have no idea! At the time, you had to download a billion files one at a time, so I skipped it . . .
I think the files were grouped sometime later to make updated the sounds easier, but perhaps not . . .
And on a related topic, there is a FREE version of SampleTank 2.5 (IK Multimedia) that is the full version but only has a smaller but nevertheless nice set of sounds:
http://www.ikmultimedia.com/sampletankfree/features/This is the download page, where you need to provide a minimal set of information:
http://www.ikmultimedia.com/sampletankfree/download/SampleTank 2.5 FREE is one download, and the sounds are downloaded separately . . .
This is nice, because it adds a lot of different types of instruments to the palette, and there are keyboard synthesizers and other stuff rather than just orchestra stuff . . .
Lots of FUN! 
P. S. IK Multimedia has one of its usual discount promotions that is based on the number of people who participate by doing something, which in this instance is "friending" IK Multimedia's Facebook page, so there is a 30 percent discount at present, but this promotion ends on March 31, 2011, so there is not much time remaining . . .
http://www.ikmultimedia.com/Main.html?fanatik/index.phpI use SampleTank 2.5 XL and most of the Xpansion Tank add-on sounds a
lot, and I am planning to get SampleMoog while the current promotion is running. I also use T-RackS 3 Deluxe for mixing and mastering, and it has some excellent processors for tailoring the dynamics of individual instruments . . .
This is an example of a
DISCO/
Pop song that mostly uses SampleTank 2.5 XL and Xpansion Tank 2 VSTi instruments, which is fabulous . . .
[
NOTE: This is what I call a "basic rhythm section", and it is done entirely with music notation and VSTi instruments in Notion 3. I use a T-RackS 3 Deluxe mastering suite on the Notion 3 Master stereo output, and I use some of the individual T-RackS 3 Deluxe processors on a few of the instrument tracks in Notion 3, mostly on the drumkit and bass guitar tracks. The Notion 3 WAVE file is converted to MP3 using iTunes. Later, I get the Notion 3 generated audio into Digital Performer 7, where I record it as soundbites and then add vocals and real lead guitar . . . ]
http://www.surfwhammys.com/Feel-Me-1-31-2011-Extended.mp3Fabulous! 
P. P. S. I also devised a way to use Reason 5 (Propellerhead Software) with Notion 3, which is done by exporting a Notion 3 instrument (typically a Piano) as MIDI and then importing the MIDI file to Reason 5, followed by doing whatever I need to do in Reason 5 and then getting the Reason 5 generated audio into Digital Performer 7 via ReWire, which is a bit beyond mind-boggling, but it works . . .
When I first started with Notion 3, all I knew was a bit of music notation stuff, but after a lot of work over approximately nine months I discovered who to get everything working as a complete system, and it is quite amazing what one can do with on the Mac with Digital Performer 7, Notion 3, Reason 5, Miroslav Philharmonik, SampleTank 2.5 XL, T-RackS 3 Deluxe, ReWIre, and so forth and so on, as well as a bit of MIDI, really . . .
There are a lot of rules and quite a few of the rules are pretty strange, but so what . . .
It is accurate, reliable, and repeatable, which is what matters to me, and it sounds a lot better than the stuff I was doing with real instruments, although I continue to use real lead guitar, since it is my primary instrument, as you can hear in this instrumental song done with real instruments, really . . .
[
NOTE: Electric bass guitar is another primary instrument, and I do a bit of drumming and idiot savant keyboards, but VSTi instruments work better for everything except the very rapid textural electric bass guitar, idiot savant keyboards, rhythm guitar, and lead guitar, as well as a bit of hyperactive Latin percussion . . . ]
http://www.surfwhammys.com/music/Dreamwalk_1.2.mp3[
NOTE: This is bit of idiot savant grand piano, which was composed and performed on the fly in real-time exactly one time, although I ran it through cascading sets of echo units, which makes it appear to be a bunch of grand pianos. There is no way I can do this with music notation, and it actually is played on a KORG Triton Music Workstation (88-Keys) using a Grand Piano preset, since I cannot fit a grand piano in the sound isolation studio, but so what . . . ]
http://www.surfwhammys.com/music/11_Starlight_2.2_Grand_Piano.mp3Really! 