Might i also recommend you take a look at
http://crystalfontz.com they sell alot of great stuff, which i have personally had good experiences with and are generally much cheaper than MO. Are you looking for a graphical interface or will text based do? The easiest thing to implement would be a serial text LCD, followed respectively by parallel(HD44780 compatible) text LCD, graphical LCD and then (phone or calc), etc. If i were you i would use either an HD44780 compatible LCD(these can be had for about $10 or less surplus depending on size) if all you need is text or a crystalfontz or MO graphics display if you need graphics, because of the amount of support information you can find on these, both from their manufacturers and other sources. I would't worry too much about all the buttons and other frills on alot of the MO displays because its much easier to just hook some buttons directly to the controller. Our team is planning somehting somewhat similar to this. Before i started writing this post i was working on adapting the default LCD library provided by Microchip to work with our controller. I wish you luck on this project.