BestCrypt ($60, 21-day free trial) is a file-encryption tool that focuses on the creation of encrypted containers. Each container file can be any size from a few megabytes to as large as an entire drive (on an NTFS drive; 4 gigabytes on FAT32). The user's individual needs will determine how they make containers, and where BestCrypt is strongest compared to competing programs I've tried (such as the free and open source TrueCrypt and FreeOTFE) is in the area of creating and managing multiple containers.
With BestCrypt, you can create container groups--for example, "Work Files," and then create containers that hold, say, a month's worth of important information each. Each can have a unique key (and probably should--having one key for all containers mitigates many of the benefits of having multiple files). The advantage here is that any container not actively mounted is virtually (assuming the password is secure) undecryptable. The container file's contents are only meaningful if it's mounted and you've entered the key. One large container with thousands of files is likely to be mounted (and thus more vulnerable, to someone sitting at your computer or connecting to it via FTP) more often, perhaps even always, whereas small container files will be mounted, written to, and dismounted. Granted, there are many use cases where this is so inefficient that people will simply not use the tool, and that's the balance point you must find.
Creation of a container is very simple--select a directory to store it in, pick a file size, and create. BestCrypt will create the file of that size, and note that the size is fixed even if there are no files in the container--a 30 gigabyte container takes up 30 gigabytes, period. It is then very straightforward to mount the container (you will be asked to format it first, as it appears to Windows as an new hard disk), and from that point on, it's just a disk drive like any other. Create folders, copy files to it or from it, etc--once it's mounted, other applications do not need any special privileges to work with it. Obviously, you need BestCrypt to mount the container, and if you forget your password, that's that.
Further, BestCrypt allows you to mount a container (on NTFS drives) as a folder, not as a new drive. This means you're not limited to drive letters, and while a new virtual drive might draw attention, a folder buried many levels deep will not be casually noticed.
What's not to like? While containers are very useful (and for many people, will be all they need), full volume encryption has many benefits as well. BestCrypt offers full volume encryption only if you purchase BestCrypt Volume Encryption as a $60 dollar add-on. Further, BestCrypt is closed source. This means no one but Jetico can be 100% sure what's going on inside the program, or check the code for possible bugs, backdoors, or exploits. This may be irrelevant to some users or may even be seen as a valuable feature by some; it's just something every user should know about their software.
BestCrypt has a fully functional 21-day trial. At the end of twenty-one days, the containers become read-only, so there's no risk of losing data you put into them if you fail to purchase the product. This is ample time to test BestCrypt and compare it to other possible solutions. It is very reasonably priced, and the feature set it offers (and the fact many businesses feel safer with a corporation, not a collection of volunteers, supplying their software), makes it well worth consideration.