yorolpal
And for other-worldly spaces and ambiences it's Blackhole and Eos. 
 

+1

As others have said, the "best" reverb is the one that helps you get the sound you're looking for (a crooner like Michael Buble probably wouldn't need the same type of reverb as a death metal band).  With that said SONAR comes bundled with several reverbs that are quite good.  Start there and see if any of them are on the right track.
 
Good luck with your search!

As Bit said it's good to have a wide range of reverbs because they're all so different and I don't think there is one which will shine in every situation. And in selecting a wide range of reverbs don't forget to check out some of the cheap or free ones too. Sometimes a "cheap and nasty" reverb fits the music more than an expensive one. On a few occasions I have found myself using some of the "cheap" reverbs you get with Guitar Rig because they worked better than the Valhalla reverbs I use on most other occasions. And sometimes the inbuilt reverb on synths is exactly what you want too, so when applying reverb to synth patches don't be afraid to stay within the synth itself. 
 
Do you have the full version of Reaktor? If so then check out the Reaktor user library for free reverbs because there are some really unique sounds in there. Reaktor ships with a great one called Spacemaster 2 which is fantastic for huge, futuristic spaces. Check out Boscomac's free Reaktor ensembles because there are a couple of great verbs in there including an amazing spring reverb. 

Okay I love the shimmer, and I just looked at Valhalla last week.  I was afraid I could not effectively use it. Are there presets for speed freaks like me? I am looking mostly for vocals and drums and I suppose guitars.  I agree that a better question would have been to specify use but the TOP THREE is great as well so. since I don't have any of those mentioned except rematrix and I also have QL Spaces which I think is the most pro sounding one I have and it has great presets.
 
I only want one right now?
 
 I used to love the SPX90 and I like the eventide samples I have heard. Should I get vallhala, its couterpart black hole? or the melda stuff? I just saw that stuff today for the first time.  If I get some melda stuff or valhalla, you guys may have to show me how to get up to speed on the controls hehe. I was born to use presets.

sharke
As Bit said it's good to have a wide range of reverbs because they're all so different and I don't think there is one which will shine in every situation. And in selecting a wide range of reverbs don't forget to check out some of the cheap or free ones too. Sometimes a "cheap and nasty" reverb fits the music more than an expensive one.  

 
These are good words.  Cheap doesn't mean bad, and expensive doesn't mean good.  A great example are the Vallhala units.  They're very affordable and sound great.

Everyone has their favorites, and you'll need to do your homework, but here are my current go-to reverb tools:

Reverberate - my sole convolution reverb, and I'd use it even more if I didn't always get lost in the rabbit warren that is the settings pages. Really my biggest complaint about all the convolution reverbs I've tried is the mind-boggling number of settings, not to mention IR files!

UAD AKG BX-20 - wow, just picked this up last week, kicking myself for not getting it a long time ago. And I should know better, I still have a spring reverb in the rack that I used to use a lot, the BX-20 will probably replace it.

UAD EMT Plate 140 - if I had to use only one reverb this would probably be it.

UAD Lexicon 224 - no, I still have no idea how to REALLY use it, second only to Reverberate in the category of too many things to tweak, but it sounds gorgeous!

UAD Ocean Way - not strictly a reverb I suppose, but it does some magic! This ends up on nearly every track I write.
Eventide 2016 - makes everything sound pretty, probably the easiest reverb I own.

Eventide Black Hole - mostly for special effects, but it is cool!

Zynaptiq Adaptiverb - I expected this to be a sound design tool, but it works well on any source. I'm still figuring it out, but I am certain this is one I want to learn.

Exponential Audio Nimbus - newest addition, the rails rival the best hardware out there, but it is complex, and getting a reverb that works in the mix is not (yet) second nature for me. I find myself overdoing it most of the  time, but when I finally get it right  (usually on the entire mix) it is glorious!

Camel Audio CamelSpace - pretty much a sound design reverb, or at least that's how I use it. It is, sadly, no longer available and I am weaning myself off it.

Wizzoverb - I had to stop using this, authorization did not survive the last system upgrade. And I do miss it.

Recently I've been experimenting with placement tools, which are closely related to reverbs, and while I have yet to choose one I'd suggest them to anyone interested in placing performers in the sound stage. They are certainly much faster than playing with Early Reflections, pre-delay, and tails! I'm trying Eareverb and VSS.

I should also admit that I still use hardware reverb, a Lexicon PCM-90 and an LXP-1 (and LXP-5). I could probably ditch the LXPs for their plugins, but the PCM-90 still sounds better (to me).

papacucku
Okay I love the shimmer, and I just looked at Valhalla last week.  I was afraid I could not effectively use it. Are there presets for speed freaks like me? 

 
Valhalla reverbs come with a ton of presets, especially Valhalla Room. 

Exponential Audio's Phoenix Verb is extremely nice.
The creator (Michael Carnes) is the man behind many of the classic Lexicon hardware reverbs.
IMO, The sound is significantly better than Lexicon's PCM bundle.

Jim Roseberry
Exponential Audio's Phoenix Verb is extremely nice.
The creator (Michael Carnes) is the man behind many of the classic Lexicon hardware reverbs.
IMO, The sound is significantly better than Lexicon's PCM bundle.

It looks like Exponential has a newer product named Nimbus ... I think it's a newer version of Phoenix.

Phoenixverb sounds beautiful, and what a great price too. It's a pity it requires a physical iLok otherwise I'd jump on it. I found this example video on YouTube. Around 50 seconds of dry recording followed by some of the large space presets. They sound very natural and musical. Oh and what a great stereo guitar recording, absolutely perfect!