A few weeks ago I bought a Kingston 2GB flash drive from my local music store. Only after I got back home that afternoon I wondered why I had actually bought it. I had no use for it (pot calling the kettle black) but still thought it could be useful in one of those moments where data transfer was needed and the network had failed hopelessly.
Robin Harris seems to think that optical media is as good as dead. As a non-read-only medium, I would agree with him. They are still mighty useful for distributing films and software, but flash drives seem to be taking over in some respects.
So in a vain effort to publicly and perhaps pointlessly sort out this conundrum for myself, I'll weigh them up against each other.
A majority of the developed world has access to a broadband connection. In places such as schools, colleges and universities, the Internet connection is far faster than those commercially available. With integration now between Office and SkyDrive as well as other non-Microsoft combinations, saving a document to an online storage provider is as simple as saving it to your hard disk - and the file is available from anywhere, including mobiles.
Flash drives for me are my last ditch alternative. It's my backup for when my Internet connection occasionally drops (feel free to detect the element of sarcasm in that). Then, I use it to transfer data from one place to another; more often than not a large movie from a friend's computer to mine or vice versa. I also use it as an ultimate backup device - in the context of needing to give a presentation and having it there in my pocket just in case the network epically fails.
Then again, for those in student accommodation living in halls of residence, they will find that their Internet speeds are throttled to act as a quality-of-service moderator for other users. That said, most student digs are supplied with Ethernet ports, so the intranet speeds between computers in your block of flats are incredibly fast. To transfer things across the Ethernet network is near instant and much quicker than transferring to a flash drive and walking to the other room.
Flash drives also have the potential to become riddled with malware which not only self-replicate once they plug in to other machines but they exploit the nature of the device itself by installing auto-starting applications. Network administrators spend many of their waking hours clearing up the mess from devices which are infected with malware as I have previously written mentioned.
However with flash drives, you have the feeling knowing that the data you hold dearly to your heart is in fact dearly in your pocket, protected and safe. It cannot be hacked into or manipulated when it is in there. You can be mugged, though. But even if you get rained on and your flash drive gets mashed in the weather, because of the solid-state goodness, the device is almost always salvageable. It's not an excuse to drop it in the bath or down the toilet, though.
Ultimately, the cloud is a highly scalable and as secure as it can get, and the flash drive in my opinion is outdated and insecure - especially in corporate/government and university environments - but more practical than optical media. When it comes down to it, user preference always counts more than what I or any other journalist says. Personally, I prefer the cloud, but simply because it's free.