-- William Gibson, All Tomorrow's Parties
onlamp has an interview with the OpenBSD devs on what's new 4.2. Basically: Lots.
The highlights for me are doubled pf performance, IP load-balancing with CARP, and layer 7 hostated support (with HTTP/SSL hackery). Marc Espie's continuing improvements to the package management system are also no doubt going to continue making my life easier.
All in all, a very exciting release! Go buy your CD!