Googlers: Apps for first time Android user?

Alright everyone, the Nexus 5 will be my first smartphone. It's arriving today and I want to know what are necessary, cool, and fun apps to download from the Google Play store? I've heard of a keyboard app named key swift or something along those lines? Would you recommend getting it?

Anyways, fire away with a list of apps I should download when I receive it, thanks!