Recommend a 3.0 USB Flash thumb drive.

[DynamicNotch]

Needs to be secure in case I lose it. Is level 4 necessary?
Also, which brand works best with an Imac?
Is a thunderbolt thumb drive necessary over USB?

 

[mmomega]

I use a Patriot MagnumUSB 3, very quick 100-200MB/s read writes.
I have a 64GB and a 128GB.

 

[bimmerboii]

The magnum is fast but is pretty huge for a usb stick.

 

[DynamicNotch]

http://usb-flash-drives.whoratesit.com/Compare/SanDisk-Extreme-USB-30-32GB-vs-Group-/1466vs10

 

[vitalion]

what about this one?
http://www.sandisk.com/products/usb/drives/extreme/

16BG/32GB/64GB

here is a review
http://www.storagereview.com/sandisk_extreme_usb_30_flash_drive_review

I have not personally test that product so i don’t have a personal opinion. on reviews etc it looks good.