I dont see a single feature that will entice me to get 700. I use my 505 to read books - thus i don't care about touch screen/dictionary/word lookup/keyboard (assuming 700 will have all of it).
Especially touch screen - i just don't see how it's better to turn pages using the screen instead of buttons - i mean, i usually hold my 505 in one hand
And that LED frontlight looks UGLY on pictures