What VST is best for Sound effects - Sweeps, Storm, Wind sounds?

Well I really like Volcano 2 from Fabfilter... it's a VST plugin that you can put on any track you want and automate filtersweeps with it or whatever you want to do with it. It's nice to overdrive the input too and there are several filter types to choose from. 

I can't say enough good things about Spectrasonics Omnisphere. It is expensive but it really is incredibly good at sound sculpting. The only downside I have found is they don't let you import your own samples. They have such an incredible library of sounds though you probably don't have to. They have some very nice presets and everything is ordered by different kinds of tags so you can call up a pad that is dark and ominous if you want to just using the tagging system. The interface unfolds from simple to very detailed so you aren't forced to face the "too much information" problem when using it especially if you are new to the program.

Almost any soft synth is going to allow you to automate cutoff frequency. At the very least there are going to be assignable LFOs for that. Omnisphere patches consist of two sound sources which can be either samples or synth waveforms. Very useful to have this combination. The modulations can be controlled by LFO's or envelopes which can be standard ADSR or custom envelopes. One thing that is really nice is that you can create a custom envelope just by dropping a midi loop into the envelope builder window such as a rhythm groove. What this does is allows you to modulate your music right to the groove which is amazingly cool. Plus, you can cross modulate the modulation sources using the mod matrix. Again, just totally great to play with.

People have said that Geist is great if you just want a huge library of patches and don't want to play. I have no experience with that. 

Zeta II is also really good but a lot different than Omnisphere in that it really is a synth. It is obviously integrated well with Sonar and you can also use it as an audio effect. Very nice if you have a sample that you want to do some sophisticated filter mods with. That said, Zeta II has a very large library of well organized presets also.

Ken

http://xenossoundworks.com/index.html

Here here Glyn.  Have you tried the Xenos Retrobank for the XILs?  Tré cool.  See it above (what is wrong w/ this web software?).  My college had a Synthi so I'm not unfamiliar w/ it, but the LE version is hard to program.  I can only imagine the full version is more so.  But some good patches by Xenos to start your mad experiements from.  And only $5 or so.

@

timidi

One thing that is really nice is that you can create a custom envelope just by dropping a midi loop into the envelope builder window such as a rhythm groove.

did not know that. sounds cool. 
you mean, you drag a midi loop from Sonar into Omisphere?

Yes just drop a midi clip in. The envelope takes the beat position and amplitude of the midi note values. You can then go in and edit further if you want. Very cool. I just did this yesterday when making some soundscapes for a video game for my daughter.
 
Ken

No problem Tim. I'm glad you're getting some info out of the thread.  I'm gettin old and lazy.  I don't like programming synths any more  - I just want to press a button and have a VST do what I'm hearing in my mind.  Like a "mind reading" VST.