I've found that it's often hard to determine how "fast" a flash drive (or flash memory) is. Often the manufacturer won’t easily give that kind of information out, almost always because it's a slow performer.
There seem to be three ways the speed of flash memory is rated. One is "class". A Class 2 flash drive should have a transfer rate of around 2 megabytes per second. Class 4 would be 4 MB/sec. Class 6 - 6 MB/sec.
Another way speed is described is similar to how optical drives specify speed - using ###x such as 50x, 100x, 133x, 233x, 300x, etc... To get the MB/sec speed you multiply the number by 150 kilobytes per second. So, 100x would be 15,000 KB/sec or about 14.65 MB/sec. 133x = 19.48 MB/sec, 233x = 34.13 MB/sec, 300x = 43.95 MB/sec.
And still, sometimes the drive either has no designation of speed, uses MB/sec or Mbps/MBps. MBps means Megabits per second, to convert that to megabytes per second, you divide by 8. For some reason (consumer confusion no doubt) manufacturers have adopted the meaning for 1 megabit to equal 1,000,000 bits, instead of 1024*1024 = 1,048,576 bits (how hard drives report capacity). So, 10 MBps = 10,000,000 bits per second / 8 = 1,250,000 bytes per second = 1.192 MB/sec. 24 MBps = 2.86 MB/sec.
Another thing to keep in mind is the speed of the USB drive. Most USB ports are version 2.0 and can operate at a theoretical 60 MB/sec. Older specifications are 1.5 MB/sec or less. A new specification USB 3.0 is shown on wikipedia as being capable of 625 MB/sec, although I doubt we'll see devices that can take advantage of that much throughput in the next few years.
I feel that there are two basic ways to go about flash memory. Get one of those rather slow USB flash drives which are convenient, or one of the plethora of other flash memory media used by digital cameras and other electronic devices. Most decent photo printers come with flash card readers (although the transfer speed may be dubious), or you can buy a flash card reader for less than $20 (Transcend seem to make popular models). Of course you’ll have to take into consideration that the reader might be a speed bottle-neck.
With a flash card reader, which you can find a fairly small one, and most connect to the USB port. Though, it might need special drivers. I don’t know for sure, but I suspect XP/Vista will recognize them without special drivers. Compact flash (CF) memory is much faster than most of the even faster USB flash drives, and are often rated from 133x (19MB/s) up to 300x (42.91MB/s). Which compared to the paltry speed of a class 6 USB flash drive (6 MB/sec) is leaps and bounds better, keep in mind that you have to have a card reader for CF memory. I suspect that due to the dimensions of CF memory, unless it can be made smaller and more compact (which might sound funny considering the C in CF stands for compact – CCF anyone?) we probably won’t see CF flash memory used in USB flash drives anytime soon. However, SDHC memory is small, and getting faster. SanDisk extreme III SDHC shows a transfer speed of 20 MB/sec, and prices are coming down.
What seems to be a type of flash memory which was introduced not too long ago (2005), and looks like it might become obsolete mostly because of the success and wide adoption of SD flash memory, and CF flash memory - is MMC(plus) flash memory (stands for MultiMedia Card) which is faster than SD memory and cheaper than CF memory; rated to transfer at around 50 MB/sec. You can buy a Transcend 4GB MMCplus card for $10 right now at newegg. It might be cheap because it’s reaching its end-of-life.
I guess it’s another one of those “too-good” things that get axed by the big executives.
This is a 32g flashdrive from OCZ for only $30 after rebate(which OCZ is good at doing. very little hassel. They commuicated with me very often and gave me updates like once a week on how the rebate was moving along). Its rugged and darn near impossible to break. Its shock proof AND waterproof. Its also one of the fastest flashdrives in the market. I've done the research and have bought it myself. Well technically I got the 16g but its still the same series. I wish I could get the 32g right now but its not really practical since I just bought the 16g. Its by far one of the best pieces of hardware I have bought.
But since the initial price is really high u may want to look for something else. Ecost has tons of deals on flash drives. Look in the bargain deals and u can quite frequently find 8g flash drives for like $5 after $10 rebate...the options are endless(several nice options that are on there frequently are the corsair and the rally). Check ecost out, I have them emailing me daily about deals...thats how much I like them.
U may also want to look at SD cards. They typically are slower(unlike another suggests above) but they are way more versatile when used with a card reader. They can go in practically any device now days and then the reader allows use with the computer. I personally also have bought a 8g micro sd card.
My 8GB flash drive is from Micro Center (so is my mouse pad, xD) and my 750GB usb hard drive is from Lacie - I'm not a usb hard drive expert, but seem to be pretty good, fast data transaction - and the Lacie was extremely cheap, it was either 100 or 150$. I could of gotten a Seagate 1.5TB for $200 but it would of had no use.