Anyone familiar with the minimalist Japanese store Muji (which has shops all around the world) will expect these three apps to be cleanly designed and stylish. The Calendar app is my favourite, but Notebook is bound to be the digital Moleskine-equivalent.
Both the Calendar and Muji To Go are free, but the Notebook app costs a few bucks - $5, to be exact. Muji To Go is a neat little app that bundles in relevant services for jetsetters, such as world clocks, Forex currency converters, weather and a cute calculator.
Calendar actually syncs with Google Calendars (though works just fine on its own, too), and is a worthy extension to their stationery line. It supports pinch-to-zoom and has varying shades of grey and red to organise events properly.
While there are heaps of sketching apps out there already, Notebook looks really minimal and works with both sketching and note-taking. It recognises handwriting and also lets you import photos and PDFs for scribbling and drawing on - which can then be emailed on to other people.
A nice way to resign from a job, using that month's PDF report?
There's a fourth app, which is also free, though it's just a glorified catalogue for their clothing range. You're probably not too interested in that... [Muji To Go, Calendar and Notebook via Recombu]