For wood I would have to say Intamin and S&S. Intamin p&p woodies are just awesome. And I rode Avalanche last summer, and it really impressed me, more than the CCI and GG coasters. Those where ok, but they didn't have any of that insane relentless feel from Avalanche.
For steel I would have to go with B&M and intamin. Don't know why everyone seem to hate them these days, as some of their rides are great. I agree that some of the newer Beemers have been a bit diseapointing (silver Bullet anyone) but I still think many of their former coasters are among the best ever built. Nemesis is my absolute favorite out of the coasters I've ridden, with Xcelerator and Speed monster in a close tied second. I would also like to mention Maurer Sohne, which in their spinners make some of the most fun coasters out there.