I use a ton of different delays - 
Rob Papen's delay is my newest, so I tend to try it first these days
All the PSP delays, their Lexi clones are really cool, and the multi-delay is very easy to program
The Cooper Time Cube from UA is my first choice for guitars, vox, and believe it or not percussion
The Echoplex from them is cool for guitar, but I don't like it on anything else
Waves SuperTap is another winner, but I never seem to remember it's there, gotta fix that!
Alchemy Audio Camel Space is amazing, I still wrestle with it, but when I get it I love it.

Lately I've been using the UA Plate and Lex224 reverbs, as well as a hardware PCM80 and LXP1. I recently picked up the Valhalla VintageVerb demo and I think that's about to become a go-to.

Both Waves and UA offer these reverbs that let you build your own spaces, I used to use them a lot, but they require a LOT of time, effort, trial, and especially error, so I don't turn to them as often.

And then there is Cakewalk's Soundstage (part of FX3) which is terrific, but getting a bit long in the tooth. I am anxious to give Virtual Soundstage from Parallax Audio a try! It looks like it may be a good replacement for Soundstage!