Obviously, onscreen personas don't always match up with one's off-screen temperament, but Michelle Rodriguez just seemed like a bona fide bad chica from the opening frames of Girlfight.  Unfortunately, her off-screen run-ins have been more memorable than anything she's done in front of the camera - which is too bad, since she's a unique presence if utilized correctly. 

Things could be turning around for Rodriguez:  she's appearing in James Cameron's low-budget, Ken Loach homage Avatar and has a part in Stuart Townsend's potentially interesting Battle in Seattle.  If those films get her career back on track, her decision to return to the Fast and the Furious franchise just to get offed in act one will likely be forgotten; if they miss, I still think she comes off a little better than Paul Walker and Vin Diesel, both of whom are short on options after numerous box office failures.

By the way, Rodriguez's demise in The Fast and the Furious 4 does not qualify as a spoiler; it's the inciting incident that reunites Walker and Diesel (sorry if I don't have their character names at the ready, but I hate myself enough as it is).  I don't know how you get revenge by participating in illegal street races, and I'm quite sure scripter Chris Morgan isn't busting his ass trying to make this plausible.  Just make sure the cars go vroom, Chris.