NOTE:  Steve Karstensen has a lot of good house rules at his never-updated Street Fighter site.  I'd suggest you read those first.

As this list became too long and cumbersome to negotiate without falling asleep, the rules have been classified into categories with their own subsections.  Some are rulings, some are clarifications on unclearly-written material, and some are alternate systems.  In general, I think Street Fighter is a well-designed game, even if it was by accident, and thus don't think it's necessary to rewrite the entire system... just tweak it a little.
 

Maneuver Rules	Combo Rules	Combat Mechanics	Rank Rules	Development Rules	Noncombat Rules
RSC Damage, Flying Tackle Movement, Deflecting Punch, Maka Wara, Grappling Defense, Turn Punch, Cartwheel Kick, Psychic Rage	Sustained Holds, Modifiers, Multiple Hit Maneuvers	Countup, Willpower/Round, Movement Modifiers, Aborts, Mr. Jab, Multiple-Hit Interrupts, Team Strategy	Approaches to Rank, Time-Weighting, Count System, Elo Rating System, Sample Elo Fight Sheet	XP Expenditure, Buying Attributes, Learning Time, Senseis, Non-Sensei Instructors, Self-Teaching	New Maneuver Creation, Insight, Ring Doctors