I have a soft spot for Zoom Reverbs but thats just me and you can't get em anymore.
Line6 Verbzilla is good with all the bells and whistles but you what people would love to say about Line6 being digital and stuff like that. I like Line6. Period. And which reverb pedal out there is not digital?
EH Holy Grail is good but you must like the presets. Personally for general usage, One mix knob is good enough. But if you want to use reverb as an EFFECT rather than a little ambience go for the line6.
Boss... waste time only.