What is the best external hard drive on the market that uses USB 2.0 and does not need an A/C adapter?
I would go with one of the Western Digital Passport series drives. Very compact, up to 500GB in size, require no AC adapter and even better, it only uses one USB cable. A lot of portable, external HDD's actually require two USB cables in order to supply enough power to the drive. WD Passport drives only use one.
6 Answers
I would recommend any of the Freecom drives. The WD Passports are OK, but I have had frequent failures with them just in general use. On top of this the plastic picks up scratches and fingerprints just by looking at it the wrong way. With the Freecom they have a great finish and are very good quality. You won't be disappointed.
There are several new companies that offer both security for your exterenal har drives. These are also cheap and offer space for all ytour data storing needs. I use the GoClickfree → Clickfree.
It works well for me
There are several new companies that offer both security for your exterenal har drives. These are also cheap and offer space for all ytour data storing needs. I use the "GoClickfree" http://www.viladdia.com/cell-phone/computer-external-hardrives-c-93_21.html → Clickfree.
It works well for me
MacLife has written a "Portable External Hard Drive Roundup" that compares, tests, and rates different portable hard drives: http://www.maclife.com/article/reviews/you_can_take_it_you_reals
I'd be inclined to look at an ioSafe (http://www.iosafe.com/3). Slightly more expensive than the competition, but it'll protect your data better.
I would go with one of the Western Digital Passport series drives. Very compact, up to 500GB in size, require no AC adapter and even better, it only uses one USB cable. A lot of portable, external HDD's actually require two USB cables in order to supply enough power to the drive. WD Passport drives only use one.