If you want a cover-flow interface for your music (similar to ipod):
iSenseIf you want a great music player with an equaliser so you can increase the bass or treble or reduce anything and actually even boost the volume
PowerampIf you want to be able to organise your films and tv shows in a virtual library
Archos Video PlayerIf you want to be able to type up essays or read other documents & pdfs and whatnot
Kingsoft OfficeIf you want to be able to see your and your friends xbox live profiles as well as check and send messages and customise your avatar you can't go wrong with
Xbox SmartglassThis next one will probably be useless to you but if you're a rugby league fan, this app will let you set your favourite premiership/league and then favourite team then will show you all the latest and greatest news in one place
RL HubFor browsers my favourite was Maxthon HD because it had a nice interface and was full HD! However this browser and every other that I tried would crash for me, maybe not for you though, so I'd recommend Maxthon in case it doesn't. If it does, then get
Firefox BrowserIf you like browsing reddit from time to time, this app lets you do it in a nicer, classier way than the regular browser version.
Reddit NowIf you're ending the day with next to no battery and finding yourself rushing back to charge it, then you need something that will let you monitor it better as well as stop resource-heavy apps from running when you don't need them, so get
Battery Doctor(Honestly, when out in London with my mates, two of their batteries had run out of juice while mine was sitting at a comfortable 60%...it also helps to only turn 3G/WIFI on when you intend to use it)
If you like keeping up to date with the latest news of ANYTHING you're interested in (be it cars, games, tech, films, comics, bewbs) then get an app that will allow you to select your favourite sites and favourite interests so it will compile the latest and greatest news in one easy-to-navigate interface... which is known as
FeedlyALSO GET YOURSELF A NEW LAUNCHERThe default launcher is shit and you're probably going to start piling your phone up with apps soon, so make the shift to a new launcher before it becomes too much hassle to organise. I'd recommend NOVA launcher or Launcher 8 (if you like the windows phone style) but there are a load of good ones. Keep downloading and trying out all the best rated launchers and see which one works best for your needs.
OTHERS:
Dialer+ & Contacts + if you get sick of the default dialer
Smart Keyboard if you aren't happy with the default keyboard layout
GAMES:
Enough necessities. How about a bit of fun?
Backstab is one of the greatest phone games ever. Think Assassin's Creed Black Flag before that game was released but without ships, but with some more surreal moments and a tale of revenge...... this game is sick
I hate the lack of physical buttons/analogs but I still completed it
It's been ages since I gamed on a phone so I'll come back here when I remember more phone games that I enjoyed :)