GLOBAL MARKETS-U.S. bonds rally after Fed; stocks retreat

* U.S. stocks end lower after Fed statement * Fed repeats to be "patient" in deciding when to raise rates * U.S. 30-year Treasury yield hits record low after Fed * Dollar strengthens after Fed * European stocks end lower on persistent Greek worries (Updates with U.S. market closes) By Caroline Valetkevitch NEW YORK, Jan 28 (Reuters) - U.S. bond prices rallied, with the 30-year yield hitting a record low on Wednesday as investors bet U.S. rate hikes were less likely to s