It seems as though you can't have fields vertically aligned to the middle of a page. The markup is generated by Gravity Form and can't be changed. Yes, CSS is something we can modify... but we cannot have UL LI markup changed to table - tr td markup, which is what would be required to have verticially aligned labels.
From this thread: http://www.gravityhelp.com/forums/topic/vertical-alignment-of-field-labels
"Because things are floated and you can have variable heights on things (inputs can be different heights than selects or textareas), there really is no silver bullet to align things to the middle of the space vertically with one declaration. The vertical-align CSS property is damn near useless these days and wouldn't work here, especially cross-browser. Line-height or padding will be your safest bet."
Can't use padding either, as it will make changes to all of the fields, and to different browsers.. it reacts differently as all the elements are floated.
I referred to http://www.gravityhelp.com/documentation/page/CSS_Ready_Classes but this didn't help either. Any ideas how to achieve this?