I go for software solutions myself. Despite the hubbub surrounding the sudden cessation of development, the standard is still TrueCrypt 7.1a.
Any cautionary messages you may hear about TrueCrypt are simply a result of the developer’s covering their ass just in case a flaw is found in the last version they did before quitting simply because they will not fix them. However, the independent security audits of TrueCrypt have yet to find any weaknesses anyways, and it’s strong enough that the NSA isn’t exactly pleased, so I still trust it. I cannot say the same for it’s forks, CipherShed or VeraCrypt.
BitLocker is strictly for the Ultimate and Enterprise versions of Vista and Win7, and the Pro and Ultimate versions of Win8. Most Win7 computers run Home Premium while Win8 is mostly the regular version, thus most lack BitLocker functionality, and BitLocker doesn’t work with OS X or Linux while TrueCrypt does.