I am Confused Which Lumia shall i Buy ..

Hi .. i am a huge windows phone fan and i think i'll be patient enough to wait for Windows Phone Store to be as good as the two giants (iOs,Android) .. After Deciding to Buy A Lumia A got very Confused !! Lumia620 very Nice Design fits very good on my little hand , classy but the battery and the Software specs were not Sufficient !! So i Thought of Lumia720 : with an impressive Battery life but with the screen Density 217ppi and the big flat design ! i think also it has the same Software Specs as the Lumia 620 ...... Then The Lumia 920 Came to my mind : Better Specs :) but after Googling some said that it's too heavy and annoying to hold .. and to receive calls holding a Brick of 185g .. will i get used to it?! ( Btw i am not very interested at photography .. ) So plz help me .. - Perfect Design and Screen Lumia 620 - Normal Screen , Impressive Battery Lumia 720 - Perfect Specs and screen Lumia 920 ??!