yes, you can actually delete your fb account now if you want to, but upon request. after confirming the 'delete permanently' button, fb will send you an email stating that, in 14 days your account will be permanently deleted.
i think fb has their reasons why they're allowing this now. i remembered writing to facebook regarding the account cannot be deleted, and had requested that they should consider the 'permanent account deletion' (well, i think i wrote them anyway, but can't remember exactly if i did or not :P). i bet there are tones of users wrote to them requesting this option. maybe fb has become too crowded and they've decided that this option is now relevant. i don't know for sure, but i'm just guessing.
for people who wants to delete their fb account,
1. login your fb account
2. then click "Help" just besides the "Home" button.
3. in Help click "Facebook Basics"
4. in Basics, find "Manage Your Account", click "Account Settings & Deletion".
5. under Account Settings and Deletion, click "How do I permanently delete my account?"
6. then find this:
"If you do not think you will use Facebook again and would like your account deleted, keep in mind that you will not be able to reactivate your account or retrieve any of the content or information you have added. If you would like your account permanently deleted with no option for recovery, log in to your account and then submit your request here."
7. click "SUBMIT YOUR REQUEST HERE" to delete account.
8. then you can permanently delete your fb account forever!!
good luck. :)