You'll find that the blue mushrooms are the best though!

For keeping them up in the air for 100 hits you get a massive 5000exp, 3 mystery goos and a couple of "awards". I found the best place for them was [spoiler] the room before the final save [/quote]. Simply save in that room then go backwards and if the mushrooms aren't there - do a soft reset and reload. Very quick and I got all the mystery goos I needed in an hour.