For bikes you need to choose either Inside or Outside drifting, Personally I'd choose these:
Inside Drifting:
Small: Bullet Bike Or Magickooper
Mid: Mach/Sneakster Bike
Heavy: FR (Bowser Bike)
Outside Drifting
Small/Med: I Rarely play using Small/Mid sized characters and when I do I do not use outside drifting bikes Sorry.
Heavy: Shooting Star/Phantom.
The inside drift bikes are harder to control, they can be very good if they have good handling as well. Because a bike like the Spear has a sharp drift and bad handling, so its super hard to control.
I choose Wario Bike, Mach Bike, Magikoopa's bike.
For starters, you should stay away from the Flame Runner, Sneakster, and Spear. The Standard Bikes make great starters.