Here is a most unusual case.  Legal Malpractice case in State Court follows personal injury  case in Federal Court and the State Court Judge effectively second guesses the Federal Court judge in  whether plaintiff was subject to North Carolina law or that of another state.

DiTondo v Meagher ;2009 NY Slip Op 29178 ;Decided on April 22, 2009 ;Supreme Court, Broome County  ends by determining that defendant may not have summary judgment.  The enjoyment is in the travel to that decision.  We have not seen a discussion of choice of law cases [car accident in state 1, plaintiff live in State 2, Car owners are corporations of state 2, etc] since law school.
"This is a legal malpractice action. Plaintiffs Joseph N. DiTondo and Caralynn M. DiTondo allege that defendants Frederick J. Meagher, Jr. and Meagher & Meagher committed legal malpractice in an underlying federal case by failing to, among other things, research and advocate the legal proposition that the federal court sitting in diversity should have applied either California or New York’s comparative negligence laws, rather than North Carolina’s contributory negligence law.

Defendants Frederick J. Meagher, Jr. and Meagher & Meagher (hereinafter collectively "defendant") move for an order pursuant to CPLR § 3212 determining that the laws of North Carolina were properly applied in the underlying federal action, on the grounds it was the site of the underlying accident and has the strongest interest in the outcome of the underlying federal litigation.

Plaintiff [FN1] cross-moves for partial summary judgment for a finding that, had defendant brought the proper facts and law to the attention of the federal court, that the federal court would have been constrained to apply California or New York’s comparative negligence rule to the underlying federal case. "

"Under the third Neumeier Rule proviso, plaintiff argues that when the law of the domiciliaries is essentially the same as here (both New York and California have comparative negligence rules) and only the law of situs is different (North Carolina has contributory negligence), courts prefer to apply the law of the domiciliaries because the situs state would have "[n]o interest in the application of its [loss allocation] law in an action between nondomiciliaries" (Marillo v Benjamin Moore & Co., 32 AD3d 1313, 1314 [2006]; King v Car Rentals, Inc., 29 AD3d 205, 209-210 [2006]). This court agrees and finds that had defendant Meagher brought to the federal court’s attention the correct facts and law as set forth herein, then Chief Judge Scullin would have been constrained to find that California or New York’s comparative negligence rules [*6]applied.

In view of the foregoing, the court finds "[b]ut for defendant’s alleged negligence, there would have been a more favorable outcome in the underlying action" (Ellsworth v Foley, 24 AD3d 1239 [2005], lv denied 6 NY3d 712 [2006]; Williams v Kublick, 302 AD2d 961 [2003]). "