I have amassed quite a few gadgets that I bring along on my travels in the region, some get quickly retired/replaced, while some make it to the "must-bring" section of my laptop bag. Beyond the regular laptop, smartphone and tablet, here are seven accessories that I recommend, particularly if you're travelling around Asia where roaming data is prohibitively expensive and power plugs can be scarce.
I've had many travel power socket adaptors, but this was the only one I've found that has two USB ports, and juices them up to 2 amps, which means that they'll comfortably charge iPads. This is only available on SQ or Tiger Airways flights, but it is good value at SGD55.
2. Nokia Asha dual-SIM mobile phone
Yes, I still use a Nokia (!) The lower-end Asha series is great for use in emerging markets in Asia. It supports dual-SIM, with a hot-swappable second SIM. Great for countries where you need multiple SIMs to ensure you're always within network coverage. Also, has a ridiculously long standby time of up to 30 days or 7 hr talk time on one full battery charge.
3. Huawei 3G MiFi E560
A mifi hotspot device like this one lets you connect your primary smartphone, laptop and tablet to the internet with just one local SIM (see item 7 on prepaid SIM cards) instead of using roaming data.
4. Lifetrons portable 5600mAh charger
This portable charge stores 5,600mAh, enough for ~4 full charges of an iPhone. It also has dual USB ports, which makes it easier to charge two devices at one go. It provides 2 amps of current, so it can charge iPads as well. The kit comes with a full set of plugs to charge anything from Sony Ericsson, iPhones to Blackberries.
5. Multi-head USB plug
I found this while on vacation in Koh Samui. It's a USB cable with iPhone/iPad, mini-USB and micro-USB plugs all in one. I have never seen this elsewhere, but presumably you can buy this at a flea market in Bangkok.
6. Belkin USB in-car charger
This small car adaptor lets you charge your devices in case you're stuck in one of the many massive traffic jams in Asia cities (Jakarta, Manila, Bangkok come to mind). Overlaps with the function of the portable charger, but for it's size and weight, it is worth packing along as backup.
7. Prepaid SIMs
I have collected a bunch of prepaid SIMs from across different Asian countries. They're cheap (~$2-5) each, and typically let you purchase unlimited data in daily or hourly 'sachets'. Keep an eye out for SIM packs with longer expiry periods to prolong the credit value and use of each SIM.
I'm always looking out for new additions to this utility kit. Do you have other suggestions? =)