T2L4* Tactical Lights

*Things To Look For
(Tactical torch torches torchlights torchlight light lights flash flashlight flashlights)

Critical

• At least 600 lumens
• Strobe mode
• Dim mode (<40 lumens)
• Can choose which mode it turns on and off in - I don't want to blind myself with the brightest mode every time I turn it on, or have to scroll through modes
• Regulated power (light doesn't get dimmer as batteries run out)
• Accepts both rechargeable lithium and disposable batteries, in case I can't charge it
• Lock-out mode
• Flat base to stand on
• Doesn't roll
• Water submersible (IPX8)

Optional

• USB charging
• "Zoomable", convertible between flood and spot, without affecting waterproofing - doesn't seem likely, I had a look and the only big brand that had this was LED Lenser
• Battery charge indicator
• Pocket clip (bidirectional is a bonus)
• Preferably side switched

Update 19 Jun 14
Here are some USB charging torches I've found:

• Nitecore MH25 - 860-40 lumens, SGD$125 on Nitecore site. 18650, CR123 or rechargeable CR123 (RCR123) batteries (can only charge 18650). Switch tends to break. Lowest setting still too high. Hard to select modes.
• Nitecore P25 - 860-2 lumens, SGD$155 on Nitecore site. CR123, 18650 or RCR123 batteries. Higher-end than the MH25, with more modes, a wider brightness range and weapon mounting. Can indicate battery voltage!
• Nitecore P12 - similar functions, modes and brightness to the P25, but smaller (2.54 cm throughout). No USB charging. 90 grams. Can indicate battery voltage!
• Nitecore MH2C - 800-39 lumens, SGD$120 on Nitecore site, USD$57 on Amazon. 18650, CR123 or rechargeable CR123 (RCR123) batteries (can only charge 18650). Similar specs to the MH25, but with a constant-width body like the Fenix UC40UE (the MH25 and P25 have heads wider than their bodies).
• Fenix UC40UE - 960-10 lumens, USD$86 on Amazon. 18650 or CR123A batteries.
• Klarus RS16 - magnetic charging connector. SGD$105 on Black Tactical. 16340 or CR123A batteries.
• Klarus ST11 - 900 lumens, SGD$100 on Black Tactical. USB charging cap S$29 more. No non-rechargeable batteries.
• Klarus XT11 Gen 4 - 820 lumens, SGD$110 on Black Tactical. No USB charging. 18650 or CR123A batteries.
• Klarus RS11 (new model) - 930-5 lumens, SGD$160 on Black Tactical (old model). 18650 or CR123 batteries with USB charging. Magnetic charging cable attachment - like Apple's MacBooks. No need for rubber port covers! Has "variable frequency" strobe, by which they mean the strobe cycles between 2 fixed frequencies, not that you can tune the frequency. I can't find the new model for sale anywhere.

T2L4* Driving Video Recorders

*Things To Look For
drive driving camera cam dash dashboard dashcam cams cameras dashcams
Since I'm getting a car, I'm thinking more about this.

• As wide angle of view as possible
• Good low light performance
• Front and back recording, if possible
• Files must be readable even if recording is interrupted - like in a crash. Either internal battery or dual recording media. Shock/crash/g-force detection. Ideally able to record the destruction of the camera itself (of course with the card undamaged). May require fancy file formats.
• Heat resistant
• Motion detection for recording when parked - this will require wiring to the car's electrical systems. Probably needs professional installation. Needs some form of power management to prevent draining car battery.
• Small and inconspicuous. I don't buy into these as a deterrent, more like an attractant. All LED lights can be turned off.
• No need LCD screen on the camera
• Removable - sometimes I don't want to leave it in the car. 
• Sound recording can be disabled
• Uninstallable without leaving any traces - if I want to transfer it to another car or sell the car or send it back for servicing (just like changing rims and tyres back to stock before servicing)
• Time and date stamp
• Does not interfere with car's wireless lock/engine start/rain sensors
• Able to format memory cards

Unrealistic requirements: probably not possible, but would be nice to have:

• Also works as an action/sports camera, like a GoPro. By this I mean water and shock resistant, has its own battery etc. Actually a GoPro would work as a dashcam, just that it can only record for 3 hours on its own battery. And it's much much more attractive to thieves than a dashcam.
• Encrypted files. Otherwise anyone who steals your camera will know where you live and where you've been

Blackvue DR530W-2CH Lite
I'm not sure if there are separate Lite and not Lite models, sometimes they use either term. I suspect the 530 Lite refers to a lite version of the 550. This is currently my preferred model, mainly because it has Wi-Fi for instant review and configuration on your smartphone, front and rear camera, no GPS and is pretty small and cheap.

Thinkware FXD900 / F550
I'm not sure what the model numbers mean, I think FXD900 is the main unit and F550 is the optional rear camera because I saw the rear camera coming in a standalone box. I'll probably end up getting this because of the following reasons (roughly decreasing importance):

1. I've found a convenient, authorised distributor that can install this
2. Unit itself has built-in power management and can be wired directly to the car battery. It will stop drawing power when battery voltage drops to a user-selectable level. All Blackvue's products require a separate Power Magic Pro.
3. More heat resistant (for recording when parked under the sun)
4. DR530W's recording framerate drops when accessing Wi-Fi
5. DR530W is said to affect car's wireless entry and rain sensor
6. DR530W's iPhone app is lousy, which is the main reason I chose the DR530W in the first place.
7. FXD900's front camera is 1080
8. FXD900 has internal memory and supercapacitor backup power

T2L4* USB-WiFi Drives

*Things To Look For

Since I wrote the post about Mobile SD Card/USB Storage Backup, I'm seeing lots of these devices (coincidentally, SanDisk just released one). If I were to get such a device, these are the features I want:

• Able to use USB drive and SD card simultaneously
• Able to directly copy files between USB drive and SD card
• Must have iOS app
• iOS app must support pictures, sound files and movies (mov, mp4, flv)
• Function as a USB battery
• 802.11n
• Must be able to encrypt storage

T2L4: Line Drawing Software

T2L4 = Things To Look For

Looking for a line drawing software with the following features:

• Text boxes with formatting. Colour, font, alignment, bullets, numbered lists, superscript, subscript.
• Connect objects with lines that move with the shapes (Word can do this). For making mind maps, diagrams.
• Draw lines by rules (pass through these 2 points, x long). I saw someone use this to explain lens design before, not sure if it was lens designing software.
• AutoCAD's methods for defining circles and arcs. Including tangent, tangent, radius.
• AutoCAD's methods for using lines to cut other lines, cut line at tangent.

T2L4: Rechargeable Battery Packs

T2L4 = Things To Look For

• Pass-through charging
• Built-in LED torch
• At least 1 A output current
• Fast/rapid/quick charging

I guess fast charging and pass-through charging mean it'll have to have its own power adapter and can't charge by USB. I can't find any fast charging battery packs. I think it's because fast charging decreases battery life cycles. Looks like they expect you to buy a pack big enough to last the whole day and charge it overnight. They really mean charge it overnight - big packs that charge by USB take more than 6 hours to charge!