For racing, most people use these;
39/17 (pretty much dead on the same as 44/16 feels on a 20")
41/18 (a little easier than 39/17, a bit faster out the gate for racing)
34/15 (bit easier still)
38/17 (spinny!)
All depends what you'll be doing and how you want it to look really, I ran 30/13 on my first cruiser and it looked nice and clean (that equates to slightly harder than 44/16 on a 20".)
If was just cruising around and messing around on Jumps though I would probably do what Hooga has done and make it harder gearing