A friend recently got the iPhone and I was showing him some of the apps I rely upon. I’ve downloaded 137 iPhone apps but of course only a handful have become a part of my life. Thought I’d also share that here – both in an attempt to be helpful and also to solicit recommendations from readers on apps they use and love.

Evernote is for notes, duh. But not just text notes, photos, web clips, voice clips, a variety of different content. You can access your notes anywhere in the world on their web site. Notes that I enter or modify on my PC or on my iPhone are then synced to the web and then synced to whatever other devices (Mac, PC, iPhone, Blackberry, others) I’ve installed Evernote on. So whatever notes I’ve got, I’ve got them everywhere.

In a similar fashion, Remember the Milk is a freebie that manages your task lists and allows you to get at them in a variety of ways. I upgraded to pro to get the bit that integrates with Gmail – I get a plug-in for my Gmail page and it integrates with my contact list there. Lots of options and repeating tasks, something I use often, are a snap to set up and manage.

mSecure is a password manager. This one costs $3 but gives you templates for storing a variety of different passwords – for the web, work, credit cards, dates, frequent flyer cards, etc. – all encrypted and password protected. Unfortunately, the only way to access the data is on the iPhone but they provide a free mBackup utility that runs on Windows and Mac.

I’ve had PushGmail (99 cents) for less than a week and already moved it to my home screen. When you get an email, you’ll get a pop-up window that not only notifies you of incoming mail, but also the sender, subject and first line of text. You can then choose to let it take you to the iPhone’s native email app or Gmail’s iPhone web page, where you can do a lot more than with the iPhone email app. The only drawback here is that I have to remember to shut off notifications before I go to sleep or the phone will be beeping all night.

Dropbox‘s iPhone app was only released yesterday and I haven’t tried it yet, but based on initial reviews, this will also end up on my home screen. Dropbox synchronizes files among multiple computers (and also has some sharing options), so that files you think you may need and that you’ve placed into the Dropbox folder are available anywhere. 2 gigs of storage is free, 50 gigs of storage will run you ten bucks a month. I just ran a test – putting a jpg and a pdf into the Dropbox folder on my PC and was able to access and view both documents perfectly on my iPhone. The pdf file is not searchable so I may shell out for a PDF reader (which I’d use in combination with AirShare) since I want to have my Nikon D300 user manual – 448 pages – on my iPhone.

I think here are about a billion conversion apps in the app store and I’ve tried a lot of them, Convert (99 cents) is the only one I’ve kept. You get currencies, length, pressure, speed, temperature, time, volume, weight, computer stuff (bits, bytes, etc.) and all wrapped up with the easiest-to-use interface of all of them.

Hong Kong Weather is so much better than the Yahoo applet on the phone that I’ve banished that one to my very last screen (and would delete it altogether if I could). It connects to the HK Observatory web site and reformats the data for the iPhone screen, supports both English and Chinese.

I use the free version of iTalk Recorder whenever I have to conduct an interview for an article. Griffin provides a free utility to transfer the recordings via WiFi from the iPhone to the PC.

Skype works so well on the iPhone that I’ve binned the USB handset that I bought for my PC a couple of years ago. The only drawback on this is that since the iPhone doesn’t allow background processes, you have to actually be running the app in order to receive Skype calls. (When traveling, I send an SMS to my gf to tell her to run Skype, then I run it, wait till I see that she’s online and can then call her for free.)

There are several flashlight apps in the app store, Torch is free and does what I need it to do. Run the app and it turns on the screen’s backlight – bright enough for me to navigate the bedroom in the dark without having to turn on any lights and wake up my gf.

Not going to get into games or some of the more esoteric iPhone stuff (like Brian Eno’s Bloom which is wonderful) but food is a fun category.

OpenRice is of course the #1 restaurant guide for Hong Kong. The web site is Chinese only (some reviews are written in English – many addresses in English as well) as is the iPhone app. I know enough Chinese characters to be able to navigate the web site pretty easily but I’ve found the iPhone app confusing to use, although occasionally useful.

I tend to forget some of my favorite dim sum dishes … or at least forget their names in Cantonese. I’ve got two apps for Dim Sum, but haven’t used these enough to choose between either so far.

Yum Yum Dim Sum sorts a variety of dim sum types by either English or Pinyin (Cantonese) names, provides a photo, brief description, the name of the dish in Chinese characters and even a “say it” button to hear the correct pronunciation.

Yum Cha is slightly different, providing the name in English, in Chinese and Pinyin (Mandarin) and a button to push to hear it spoken in Cantonese, along with photo and description. This one also allows you to build a list of your favorites.

I’ve also got these three apps for sushi but again, haven’t used them enough to choose just one so far. All allow you to build lists of your favorites. Sushipedia is the only one of the three that provides the name in Japanese characters. SushiMonger lets you rate each type on a scale of one to five stars and allows you to attach your own text notes to each description. SushiTime is probably the weakest of the three.