With my dd, I got to the labour ward, saw the pool was going to take at least an hour to fill up, and demanded an epidural.
Because the epidural didn't work, I'm thinking about pethidine this time (for my first course anyway), and as I'll hopefully be a bit more mobile I was thinking about asking for the pool again.
One major problem I have with it though is that last time I shat for England - was that a problem for anyone?! I suppose in reality I'd probably be out of the pool for that bit, but still...