I tend to bounce around on several projects, so TODOs are very helpful for keeping track of what needs to be done. I've also found that TODOs invariably lend themselves to the comments for that chunk of code.

Depends on where I am. If I'm not at home, I've got a Mac Book Pro that I use; going on a year old. If I'm sequestered in my code cave, then I've got a custom rig I built running Win 10 on 16GB of RAM, a 3TB HDD, an Octa-core AMD processor clocking ~4GHz/core, and a modest vid card pushing display out to an LCD TV via HDMI and a smaller monitor on the side that I use for showing reference material, notes, stackoverflow searches, etc.