DELTAprime :
OK, so since I just want to make it hard for someone to read my personal data should they steal my PC (which is a possibility since we have had neighbours broken into) and I have offsite backups (which I already do) then I should just go with software and if a drive corrupts just format and start over?
Yeah you could. Those thefts would be for the sale of the laptop "hey buddy want a nice Mac? Only $200!" not actually to steal your data. Even if you had a basic 'password' login, would be enough for those "my neighbor got broken into" to stop them, they aren't even mildly interested in your personal information, they would have no use for it.
Now if your CC was laying out that would MUCH more valuable as they 'burgle' your home, and easier to deal with. So while I understand what your trying to do, your over paranoid on the security (encryption) you need. Normally the encryption software wise is for businesses where your talking Million Dollar contracts / negotiations and you dont' want someone undercutting your offer / business. Plus you have a IT Team 24x7 you pay for to that "if (Windows) corrupts just format and start over" without too many productivity hours lost in the mean time.
For consumer your talking DAYS and DAYS of rebuilding the image, updates, etc. because once you encrypt the drive you can't 'back up the image', especially since Vista was released this has made it impossible (no more Symantec Ghost quick like solutions) to just build a 'backup' image then encrypt and go back to if things 'go bad' so to save yourself days and days of download and installs patches etc. then finally full encryption.
Is why the hardware solution while costly is a real time saver and much less risk of 'OS' screwing up the entire drive to start all over again. Up to you which path you want, but personally (as I suggested) I wouldn't and don't do either at all for PERSONAL use, too much risk, not enough gain.
Oh and one big 'POP" to your bubble. IF you use the default autologin, and your saving your cookies / PW for all your using Paypal, Bank Acct, Credit Card, Bills, etc. once they get past the LOGIN PW (especially if it autologs in) encrypting the drive doesn't do anything, they are 'in' by just logging in. The encryptions is best for those trying to remove the drive and hook it up to a secondary system preventing them from 'reading' the drive.