I have Holeshots XC's all the way around on my 400ex and my Warrior. I like em alot. I ride on mostly dirt, rocks, mud, and gravel. They do the job in most any conditions. Don't forget the Douglas .190 aluminum wheels to go with them. Much lighter than the stock steel wheels.
On my 400ex: front 22-7-10
rear 20-11-9
On my Warrior: front ? can't remember? sorry
rear 20-11-9
Maxxis Razrs are also very good tires. My buddy runs them on his 300ex and loves them. They have alittle more sidewall flex than my Holeshots.
Holty
2002 Honda TRX400EX
-Full PRM Skidplates & PRM Baja Bumper
-K&N Filter, Jet kit, & White Bros. e-series pipe
-ITP Holeshots on Douglas Wheels
-Graydon Case Saver
-Works Connection Pro Perch & Lever
-OMF Scoops
-LSR +2 Axle ,LSR Bearing Carrier, & LSR Brake Block Off
-Elka Triple Rate SSD shocks & Houser +1 A-Arms