Grid view is not quite as important to me as it was, but I think it deserves to be at the top of your list.
My remaining votes went to the following three items, and I would like to express more directly what I'm hoping for. Now that I've created a database I'm very pleased with, my interest is shifting to making the best possible use of the information. For me, the ability to use the program in a home theatre environment (i.e., viewing at 3 metres, using a remote control) would offer the greatest improvement to it's utility. The addition of a typical Media Centre-like "theatre view" is far too much to ask, and is probably not exactly what I'm looking for anyway. I'm hoping the interface customization features will be implemented in a way that will allow me to create my own PVD "theatre view" that includes as much information as possible—enlarged to readable size. The result would not only allow me to select a movie for viewing (as media centre software would—based on attributes, covers, etc.), I would be able to see most of the movie information, read a review, etc.
I'm sure I'm overlooking some complications, but this capability doesn't seem to involve much more than the ability to increase the font size and maybe rearrange some of the fields to better accommodate the larger font. It would require the ability to save customized views and switch between them easily (e.g., a shortcut that toggles normal/"theatre" views). Most of the navigation issues can be dealt with in programming the remote. In other words, I can imagine a "customizable views" feature that would satisfy my specific need, as well as the more general desire to tailor the interface to one's own preferences.
More features:
A fundamental feature that sets PVD apart from others is the handling of people in a proper relational database. I think it would be wise to highlight this by offering a third panel or pop-up that shows the (complete people view) information for any person selected in movie view. This would make the people information much more "accessible" than it is now. The time lag in switching views is a significant deterrent to viewing people records on a slower machine. I suspect it's at least an annoyance at times on a fast machine—having to switch views just to see some information about a person in a movie. I suppose the same should be considered for movies in people view, but this would not interest me nearly as much.
Well, okay, it's not a new feature, but... On behalf on new users, I would like to vote for any improvements that will make import/export routines easier to use. The obvious thing that comes to mind is the ability to read headers of input files and present a field mapping dialog populated with the fields found. Many potential new users are going to have existing data they are very attached to. Even though the existing routines are effective, some are not going to even try PVD unless they see a clear and easy path for converting/importing their existing data.