Thanks for all the informative replies guys. Seeing that I already have decent hardware, I'd like to use it, especially as, coming from a gigging background (a hired gun for more years than I care to remind myself!), I'm very familiar with the boxes in the rack. Also, as Anders pointed out, "even the manufacturers state that they are 'approximations' of the sound and not identical", so there is a place for both I think.
I will still of course use my plug-ins as some of them are excellent but to be honest, some plug-ins are not great. I like the 'feel' of faders and knobs (old-fashioned again!) and I want to be in a position to use plug-ins or hardware when the time is right.
I realise that it's important to record a dry vocal but for some singers, especially those who perform regularly through a decent PA on stage, it's much easier for them if they can hear something approaching their 'stage' sound in the headphones. I think ido1957's advice is good for me, a subtle comp and reverb going in will usually work.