If you are looking for some great sound effects that you can actually use look no further than Designer Sound FX. This is a great product from Andrew Kramer of videocopilot.net. He as many useful products that I can't live without and this in no exception. There is too much here to list but here is a quick rundown of what you will receive:

•  500 Sound FX & Audio Elements
•  Royalty Free Sound FX for all your productions
•  After Effects Project File for this Promo
•  Free Tutorials and Extras!
•   2-DVD Set jammed full of extras!

Bonus Extras & Tutorials:
5 Video Tutorials: Learn to Plan, Mix, Score, Animate, Sync and Render
Learn how to create audio scores like the one above using Designer SFX

 5 Pre-Scored Audio Tracks with AE Project Files (Royalty Free, AE 6.5+)
Use, Rearrange, and learn from these 5 pre-made scores or design your own

  Entire Promo Video Project File & Footage (AE 7)
See how everything was created and manipulated from start to finish.

If you want to make it snow in your world After Effects has the solution. The CC Snow plug-in comes standard with your After Effects application and is a great way to add snow to a picture or movie and adds realism. I added and extra layer to my example so that it could snow at an angle, this not only adds realism but a deeper, almost 3-D look to your snow. You can change the rate of fall, amount of flakes, how large your flakes are, opacity and many other useful settings. This is not a plug-in that you will use on a daily basis but when you need to make it snow it is worth its weight gold. Make sure you sign up for our latest After Effects class and learn how to use this great plug-in and all the great features that Adobe After Effects has to offer.