I have had an 060 board and whilst its ok, I love the 68030 CPU its a true 020 compatible instruction set and runs everything like an A1200 only faster. I wouldn't go back to 060 on my A1200 now. Regarding the 040, its my least favourite 68k CPU as it always seems to be left wanting as the 060 is faster and doesn't give off so much heat, yet with both they still need their own library.
Regarding PPC, mmm, they go for silly money, I bought a Sam400EP with OS4.1 for around 250 pounds - just the PPC card on its own would be much more than that (I would be lucky to get a straight 68060 board for that come to think of it).
For WHDload stick to your 030 IMO if it is a full 030 you can run 68k Linux... much more fun than easy-peasy PPC linux. OS4 again would be better on a new Amiga.... IMO again of course.
