I'd be shocked and amazed if someone broke into my locked computer. Someone could break into my house with something as simple as a rock, though.
Finally, there is the eventual cracking of many encryption algorithms via cryptanalysis and moores law.
[1]: Answer about moore's law effects on bits of security http://crypto.stackexchange.com/a/1828 [2]: http://en.wikipedia.org/wiki/Cold_boot_attack
With FDE and memory encryption, how else can you get pass this?
Securing your data is a completely different problem, and a much more difficult one, than securing your house.