Xperia Z, first android & apps

It's pretty high end so can run probably run any application without lagging. My usage is fairly basic, I'm not a big phone gamer but usually when I get a new phone I'll try out a few launchers if I don't like the stock one, download Sygic Aura maps, install a two security applications (SeekDroid & Cerebus), Cerebus is great, I have it setup so if I or someone else enters the wrong pin code on my phone it'll take a photo with the front camera and send it via Email to me so I can see who is trying to get into my device - I can track it via GPS as well if it's stolen. Generally I install PocketCasts, Google Music and TuneIn Radio for my audio applications and MXplayer+codecs for videos.

I use Tasker in conjunction with Secure Settings to automate a few tasks such as forward SMS messages and missed calls to my Email, eg. if I leave my phone in the car or at home I can still get incoming messages/missed calls. Falcon Pro is a popular Twitter client at the moment if you use it & if you surf a lot of forums then Tapatalk can help organise them.

All depends on what you like doing on your phone and if the stock software is good enough. I like aftermarket software a bit more then stock stockware, eg. original timestamps of when SMS messages were sent from the persons phone so I use a aftermarket SMS application, I use exDialer simply because the UI is so nice.

There's so much to customise and sometimes it can be a chore for new users but once you get everything you like it can help make your phone experience a lot better.

So basically take a look at categories like launchers (Nova, Apex..), keyboards (Swype, Swiftkey..), navigation software (Sygic, TomTom..), file browsers (Solid Explorer, EStrong Explorer..), weather apps (Google Now, Yahoo Weather..), adblocking (AdAway - requires root most of the time), carrier usage apps, social apps (Twitter/Facebook..), Dialer/SMS apps (exDialer, GoSMS..)

There's just too much to list and if you're a power user or not.