True Apps do depend on your interests.. Some of the Apps iv got are..
1.Handcent Sms (Free and Awesome App for Messaging If you do that a lot. With free themes as well)
2. QuickPic (Free and Awesome App for your Pictures & Videos, even hides stuff which you dont want to share with people)
3. Go Launcher EX (Free, if you dont like the standard Sony launcher with additional screens. You can download some of its themes of the Market. But not many themes are free)
4.Pixlr-O-Matic - (Free App for editing all your pictures. I find it one of the best out there. Plus its free what more do you want)
5. Juicedefender & Advanced Task Killer (both Free Apps to save your Battery and Kill Apps that you arent using which would take up your memory and battery)
6.Avast Mobile Security (Free Anti Virus. Always Handy to Keep One)
7.N7Player (Free Music Player, really good if you dont like the Standard Music Player)
8. Whatsapp (Free for a year, Like BBM, But since you dont have a BB, this comes in handy)
9.Zedge (Free App source to get Wallpapers, Ringtones, Notification Tones, and Now even Live Wallpaper, Games are also available with their new Update)
10. Alarm Clock (Free and really Helpful for me when am Shooting)
11.Solar Charger (Try it out if you want you Never know when you might need it)
12. Skype (If you travel a lot and Miss your loved Ones)
13. Angry Birds:Space (Awesome), Contract Killer, IPL Fever (if you like Cricket),Fruit Ninja, Skater Boy (Addictive Game), Tank Recon(Lite), Temple Run. (All free Games which you just mite like)
14. Mumbai Taxi Autorikshaw Meter (If you live in Mumbai this will definitely come in handy. Its free and updated)
These are just some of the Apps i depend on. Hope it helps..