Love reverb. I haven't used it live but at hoe through headphones it gives a real ambiance like you say, and fattens up the groove. It also pairs really well with synth bass, leading to some really cool sounds.
With my mini bass (avatar) I tend to assign reverb mix to the knob on the bass and when playing solo it makes for a really warm and 'full' sound.
It took me a while to realise what it was that made some slap bass samples i heard sound so good - I can't remember who they were but IIRC it was an online library of bass sounds I used to listen to now and then. One of them, I think it was a Celinder jazz bass, had a touch of reverb and it sounded great - I didn't have a reverb pedal at the time but as soon as I had one I was thinking this is what I was missing - now it sounds weird playing without it!