Empress Wu is probably the largest hosta. I noticed several sports are available.

I grow Empress Wu, and it is large, but the leaf color/texture is nothing super special. It does have a good form: leaves spaced well and held upright.

Wu-la-la is one sport. It's available from more than one nursery.

Gabriel's Wing is another sport.

I'm not sure how large these will grow, or if they are even that great. There is more than large plant size to consider. Facets such as color, texture, flowering, etc. are important. Maybe a slightly smaller hosta, such as Liberty or Victory, might actually be better. Thoughts?

I was looking at the Wu-la-la and Gabriels Wing pictures, they really don't do much for me, I have Empress Wu and like it for the pure size, but I would go for Liberty, beautiful colors for a Hosta, when the light hits it, it really lights up the spot. JMHO

Here are a couple more:

Holar Ice Empress, which makes medium to large size plants. Holar Ice Empress is actually a hybrid, which may explain why it only makes medium-sized plants.

Wunderbar, which is said to make giant plants.

'Kingsize' is another sport of Empress Wu, one that lacks the glaucous coating.