If designing new crypto stuff, use a mode like GCM (Galois Counter Mode) or EAX. Avoid the old non-authenticated modes.
If you need to encrypt something, I recommend NaCl: http://nacl.cr.yp.to/
Also, I'm under the impression that NaCl achieves impressive speeds, but at the cost of using implementations tuned to a specific CPU. This makes the amount of code that has to be reviewed considerably larger.