Most of what you are hearing are very short delays(to create a more natural ambience). I would say if you are going to use reverb, the secrets are panning(sometimes mono works best), diffusion(go with shorter numbers they simulate darker sounding rooms)and pre delay. Also you can have some of your vocal delays trigger the verbs. One of my tricks is that I use a stereo delay on a lead with different times on each side. I might have the left side panned to lets say 8 oclock and the right(shortest delay time with EQ) and panned slightly off center. I send the left delay out to the reverb and pan the reverb return maybe 9 oclock or slightly more right. That way you create a space for your lead(more present in the middle) and give it some space as it tails away(from left to right). It also depends on what is going around the lead, but I think you get the picture.

thanks, sounds good.... I'll do some experimenting.....