This D compiler uses the DMD front end and the LLVM backend. It is very up to date, generally produces the fastest code of all the D compilers, and comes bundled with tango. A significant downside is the lack of exception support in windows (this is a LLVM backend issue).

LDC is an implementation of D. Other implementations of D.
LDC is an example of a compiler. You may find the programming tasks that have been solved using it here.