The best replacement for truecrypt is bitlocker.

The best alternatives to truecrypt are rated as following:
★★★★★  bitlocker
★★★★  pgp
★★★  luks
★★★  axcrypt
★★  freeotfe
★★  efs
★★  boxcryptor
★★  filevault
★  encfs
★  filevault 2
★  diskcryptor
★  7zip
★  knox
★  bitlocker windows 8
★  drivecrypt
★  hardware encryption
★  gpg
★  dm-crypt
★  folder lock
★  encrypt stick
★  bestcrypt
  disk utility
  cryptainer
  symantec pgp
  ironkey
  compusec
  pointsec
  realcrypt
  keepass

Your alternative for truecrypt is not listed? Suggest!
Speaking about truecrypt, one probably shouldn't forget about dropbox.

Other search terms related to truecrypt and their ratings are:
★★★★★ dropbox
★★★ google drive
★★ pre boot authentication
★ yubikey
★ dual boot
You have in mind a companion for truecrypt and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of truecrypt in all years. Click on graph for more.
truecrypt
bitlocker
pgp