If you mean 7.00 then snow and steppe terrains, new charger models, new pricing system, damage changed for weapons, one ahnded and two handed weapons. Lods of changes, about ten times that.
If you mean 7.03, that was MAINLY a bug fix.
EDIT: Here's what aramgan said about 7.03
Hi folks!
A new version of Mount&Blade is ready. This version has a few fixes and changes but its most important apect will be that I'll release the module system for it in a few days.
Here's the changelog for the new version:
Melee hits to a horse consume %40-60 of the damage now permitting some of the damage to be carried to the rider.
Reduced probability of horse becoming lame from 30% to 20%
You can switch to shield without carrying melee weapons now.
Increased damage penatly for using a two-handed weapon with one hand to 25%.
Troops properly equip gloves now.
Some minor bugfixes.