I would say Baron Davis is the better player as well as the more important player for your team. He's a very talented point guard and Jason Richardson is an above average shooting guard. Shooting guard of Jason Richardson's caliber is easier to findl while it's much harder to find a point guard of Baron's talents.
I thought everyone voted for Baron judging from the comments so I voted JRich, who actually got few votes and that kind of suprised me.
Anyway, though Baron Davis is indeed a 'better' basketball player, one shouldn't ignored the leadership quality JRich has displayed this season. JRich has totally won me over since the begining of the season.