The answers for your questions depend on what your goal is. If your goal
is online anonymity / security (as in "not getting malware from web
sites"), as you stated in a previous message, then encryption is useless
on your threat model.
And my opinion on TAILS is a nice prepackaged linux distro for unlikely
extreme situations I won't easily find myself in - I'd be long dead
before reaching the point of needing TAILS.
It seems to me that you do not have a clear idea of what you are trying
to obtain; first, focus on what you want - it may help figuring out your
"enemies". Then design a security strategy around the threats. Then you
can choose the right tools to fulfill those strategies.
I have a laptop and a workstation. I use fedora with full disk
encryption on the laptop, because my enemies are casual thieves that may
steal my laptop and I carry work-related private data, but it's only
used for work demonstrations, so I don't need isolated domains nor high
network security. My workstation is instead used for reverse
engineering, developing, remote administration through ssh, and personal
things (involving 2 skype accounts). Here I love Qubes for the isolation
it provides between work/personal/skype/reversing(dangerous) domains,
and I'm less afraid of it being stolen (or any evil maids) - so I have
no problem with it being put to sleep instead of being completely turned
off. I don't have modeled any institutional enemies, because they are
expensive to defend against, but I have some threat models for the
workstation too - namely, the skype for linux monolithic binary,
possible malware from the reversing work, and unknown exploits in the
firefox browser.
To answer your question, anyway, any full disk encryption
(luks+cryptsetup, bitlocker) may suffice if your adversaries are not
going to spend a lot against you. I do believe in thermorectal
cryptanalysis above technical sophistications unless lives are at stake.
--
Alex