OpenBSD currently ships with a slightly modified gcc 2.95.3, which 
should be adequate for most people.

Selected changes:

* gcc 3.2 is much slower compiling than gcc 2.95.
* integrated preprocessor, somewhat better diagnostics.
* much better C++ support, almost fully ISO compliant.
* better C++ template diagnostics.
* better code generation, (scheduling on newer intel platforms), sparc64,
and others...
* function at-a-time compile and tree based inliner, that should give
better results than the old inliner.
* profiler-directed optimizations.
* built-in for mmx (needs new gas though) or altivec.
* integrated ada and java compiler (boehm-gc does not work on OpenBSD yet).
* more robust, especially where odd compile options are concerned.
