I’ve been using the iPhone for nearly 3 years and iPad for nearly two years, and I’ve bought NUMEROUS apps. But, which apps do I actually use frequently or find them useful? I’ve finally decided to make a list:
Apps that I use on (almost) daily basis
Apps that got both an iPhone version and iPad version (universal or not):
Mail and Safari: Indispensable.
Calendar – I use a Mac. It syncs really well across my iMac, iPad and iPhone.
Reminders – I’ve got tons of to-do apps but eventually I’m using Reminders. Simple and syncs well and …Siri integration on iPhone.
BibleReader (universal)- A Bible app that I’ve been using since Palm era. The NIV Bundle that I bought almost 10 years ago is now working on my Mac, iPhone and iPad. Notes and highlights can be synced across platform. The best Bible app so far. In-app purchases work on all platforms as well. I’ve bought Bible dictionaries and various commentaries already. I like the split screen option that allows me to pull up both NIV and Expository Commentary at the same time. The way it shows up linked scripture is unobtrusive and intuitive. Really helps in studying the Bible. It actually makes me want to read the Bible more often.
MobileRSSI like the iPad version more but it’s easier to read on iPhone on a crowded train.
GoodReader – This app just gets better and better. I really regret having bought iAnnotate like two days before GoodReader enhanced their annotation UI and tabbed view (=_=!). The ability to add two different DropBox accounts and various FTPs is really helpful. It also allows you to edit TEXT files. It supports a WIDE range of file formats as well.
Facebook – Well, what else can you do with Facebook other than… Facebook-ing?
IM+
– Stay connected with friends on MSN, Facebook, ICQ, AIM…etc (And stay invisible when I want / need to)
iPhone:
Clock – I do use the clock to set alarms.
Phone and Messages – I do use Messages a lot more after iMessage is activated.
Camera – I use it mostly for video taking in lesson (taping my students’ playing – I teach piano and violin) or when I need quick snaps. For still photos, I use the next one below…
Camera+ Extremely useful camera app. Nice filters with good integration with Facebook and Twitter.
MoneyWell I use MoneyWell on Mac to keep track of my expenditure and income. They sync through DropBox.
Whatsapp – Stay connected! (And stay invisible when I want / need to)

iPad:

ForScore – Indispensable app for musicians and music teachers. I’ve put MANY scores (in PDF) in this app (1.1GB now) but it rarely crashes. It has half-page turns which is really useful. It also allows you to annotate the score with musical signs and high-lighters. It also provides a way to mark DC, DS, repeats, and Coda so that you can jump to where you need to by one tap. US$4.99 well spent.
Noteshelf – Best note-taking app I’ve tried so far. I’ve bought TONS of note-taking apps (I’ve even written a detailed review on all these apps) but this is the app that I use most frequently. It takes hand-written notes and, with the latest update, typed notes as well. Images can be imported into the app for annotation. Notes can be exported as image or PDF. Export options include Email, Dropbox, and Evernote. BTW, the UI is really beautiful yet with no compromise whatsoever on functionality. US$4.99 well spent again.
Apps that I don’t use on daily basis but find really useful:
Apps that work on both iPhone and iPad
PlainTextA nice universal FREE app for simple note-taking. Integrated with DropBox. Clean UI made just right.
PagesI take meeting minutes with Pages on iPad. I have QuickOffice too but I rarely use it. Pages is way more elegant. I usually just send minutes right from my iPad to my PC-user colleagues and they never complained. So… I think compatibility is not an issue. (Well, I do avoid using tables but lists are just fine.)
iBooks – I guess it’s because I never really bought books from Amazon so iBooks is the app I turn to when I read ebooks. And I do buy ebooks from iBookStore. I don’t read PDF on iBooks, though. I use GoodReader instead.
AppShopper – INDISPENSABLE app for all iDevice users. (Well, there’re many apps for the same purpose out there. They’re all good… just grab one you like!)
iPhone:
Japanese – A well-built Japanese dictionary, phrase book, and study tool app.
Dictionaries – Oxford Music Dictionary, Merriam-Webster Dictionary, Cambridge Dictionary…etc. I usually buy dictionaries when they are free (Oxford Music Dictionary is probably the only one that I actually paid for). Besides, now we have built-in dictionary on iPhone and iPad (select word > define). I have a couple French and German dictionaries as well.
Cardmon – a nice little app for making cards to email or post on Facebook. (I got it when it’s free.)
Flava – a nice little journal app that takes photos, map clips, text notes etc. Integrated with Facebook, Evernote, Twitter etc. (Again, I got it when it’s free.)
Genius Scan – Best scan app I’ve tried so far. Excellent B/W rendering. Creates clean and crisp PDF / JPEG images.
iPad:
Skitch Great Free app for quick annotation on pictures / maps / web clips.
(I began writing this entry on WordPress web version on Safari but it was PAINFULLY SLOW. Adding hyperlink to text is such a cumbersome work. Eventually, I opened up the long-forgotten MacJournal app and phew… so much easier. I begin to like MacJournal…finally.)