ColoradoChris wrote:My only concern with any of these closed-source programs would be built-in backdoors
Maybe it's not what you meant, but TrueCrypt is actually open source. I don't know the other two products you mentioned, but based on my little experience I like TrueCrypt a lot. (And by "little experience" I mean I haven't used it for encrypting a lot of stuff even though I have used it many years. My needs haven't been that big so far.
There's another open source software quite similar to TrueCrypt that has also a trusted history of many years: FreeOTFE
. Maybe you'd like to check out that one as well, although I think it may have a slightly bigger learning curve than TrueCrypt.
I've heard positive things about PGP (now Symantec-acquired) and debates on which algorithms are best.
Robert J. Hansen, a former cryptographic engineer for PGP Security, likes to put it this way every time the question about different algorithms comes up on the gnupg-users mailing list
"Just stick to the defaults".
Meaning, the default algorithms that different OpenPGP software products offer are usually the best ones for common users, unless there's some specific need or an algorithm is suddenly broken (which usually is a longshot). By using those — and not some exotic combination — it's the most likely you won't come across any compatibility or interoperability problems when using them with other people.
But there's really not a single "right" answer for "what is the best cryptographic algorithm". David Shaw, one of the developers of GnuPG, once used this nice allegory (ref
It's important to note that we're talking about tiny fiddling details here. Either path is so vastly stronger than is usually needed that this is rather like discussing whether a 1001-foot fence is better than a 1000-foot fence: sure, 1001 sounds better, but if you have an attacker that could get over a 1000 foot fence, it's safe to assume they can make a pretty good crack at the remaining foot.
Basically, use any algorithm PGP offers, and you don't have much to worry about.