1. Generation X (Husk, Monet, Skin, Penance, Banshee, etc.)
2. X-Factor Investigations (Madrox, Layla Miller, M, Rictor, Darwin, etc.)
3. X-Corps (Banshee, Sunpyre, M, Husk, Jubilee, Blob, Avalanche, etc.)
4. Genosha Excalibur (Callisto, Xavier, Wicked, Karima, Husk, Archangel, etc.)
5. Exiles (Blink, Morph, Noctune, Sunfire, etc.)
6. The Six (Havok, Bloodstorm, Brute, Iceman, Fallen and Goblin Queen)
7. New Excalibur (Sage, Pete Wisdom, Juggernaut, Nocturne, Dazzler, etc.)
8. Original Excalibur (Shadowcat, Phoenix, Cap Britain, Meggan, etc.)
9. Storm's X-Force (Spiral, Puck, Psylocke, Bishop, etc.)
10. Dazzlers X-Treme Team (Sage, Dazzler, James Howlett, Corporal Summers, etc.)

I thought about ranking them higher, but I just couldn't resist having The Six at #6. ;P