First, I would search for Rudy Huyn on the store, he is a developer for apps and his apps are top notch. I would also recommend getting Baconit for a great reddit app and audiocloud for a sound cloud app. Battery Pro +, world clock, bing sport, grin, fresh paint, didlr, shazam, stock watch, counters and level are all very neat apps as well. Other windows phone worth downloading are.
627.AM : Alarm App, really useful and good looking.
Adobe Reader : For your .PDF files.
Flashlight : -
Phonly : RSS Reader/Feedly client.
NextGen Reader : RSS Reader/Feedly client.
Fotor : Photo editor.
Aviary : Photo editor.
MyAppFree : App deals.
UC Browser : Browser.
YouTube HD : Watch & download videos.
SophieLens HD : filters cam, all filter packs for free until November 22.
Search for Nokia corporation, download almost all apps (cinemagraph, creative studio, panorama, smart cam)
If you like football get GoalLive.
Photosynth: create cool, "photorooms".
Where I am : discover your location & places near to you, restaurants, stadiums