I dont use software reverb much within the DAW.....if I were looking for good reverb plugin I would certainly check out the Lexicon PCM Native Reverb bundle. Its not cheap at $600 but from what I have heard its the best of Lexicon sound without the hardware cost which is somewhere at $2000 new. At one time you could buy individual plugins within the bundle, not sure if thats still availablehttp://www.lexiconpro.com/en-US/products/pcm-native-reverb-plug-in-bundle
I had the demo of Aether which I did like but never did buy it for the reason I mentioned but I was impressed.http://2caudio.com/products/aether/#_overview
T.C. Electronics Vss3 reverb which was original part of their Powercore platform is a plugin ported over from TC's 6000 system. I used it alot when I had a powercore pci card in my old Mac G5 so the software is no longer. I miss it and would put it up against any high end reverb hard or soft. For those in the Pro Tools dominion you can still get it as a TDM pluginhttp://www.tcelectronic.com/vss3-tdm/
As for other software plugins for processing audio......the one and only Sound Toys native bundle. I recall Paul Vnuk saying on this forum that a good software reverb and the Sound Toys bundle of fx plugins you can come very close to the sound palette of an Eventide Eclipse. As an Eclipse owner and Sound Toys user I would agree with this. http://www.soundtoys.com
As to converters....the title of this thread. There are so many options. I dont think today there are really any bad converters out there. It seems a very competitive market where manufacturers cannot afford to put out inferior products. An all in one box would be my choice. Pre amps, converters monitoring etc under one hood. Im actually looking at a Metric Halo ULN8 unit as a possible option for myself. Its high end with a price tag to match but I would be selling high end gear to make the purchase as I consolidated my studio.
I would advise to buy right the first time and have it for life so to speak.