Why does the Torah add, "Em Yaakov v'Esav"?
Ramban: Seeing as Lavan was Esav's uncle as much as he was Yaakov's, Yitzchak ought to have instructed him too, to go there to find a wife. And the reason that he did not is because it was Yaakov on whom he wanted the Berachah of Avraham to take effect. 1
Rabeinu Bachye #1: The Torah writes this in praise of Rivkah, who ought to have loved Esav at least as much as Yaakov - if not more since he was the Bechor. Yet she loved Yaakov due to his beautiful Midos.
Rabeinu Bachye #2: It is the reason that Rivkah chose to send Yaakov specifically to Lavan - since they were equally related to him, and he would not permit the one to kill the other in the event that Esav would turn up there.
Ohr ha'Chayim: Do not ask why Yitzchak told Yaakov to marry a Rasha's daughter, for a chain of Kedushah cannot come from a Rasha (Lavan). 2 Rivkah and Yaakov came from Besu'el! Also "Achi Rivkah" hints that also Tzadikim can come from Resha'im!
Ha'amek Davar: Because she was mother of both of them, Yitzchak and Esav did not sense that Yaakov went to her brother to flee Esav.
Gur Aryeh #1: Yaakov and Esav were brothers, yet they were diametrically opposed. 3 Yitzchak knew that the blessed nation could only stem from offspring that was fully worthy. Seeing as Rivkah had borne mixed offspring, this had not yet happened. Yitzchak sent Yaakov to marry into the family of Lavan, Rivkah's brother, where he would father a unified, blessed family. 4
Gur Aryeh #2: Rivkah was the mother of two children who were called "nations" (25:23) from the outset; and Yitzchak understood that this ability was inherent in Besuel's family. He sent Yaakov to marry into the family, so he could father the blessed nation.
Ohr ha'Chayim: You cannot learn from Avraham, for he did not command to marry specifically Besu'el's daughter, and Besu'el was not known to be a Rasha. Before Klal Yisrael was founded, they needed to pursue wives from elsewhere (Avraham's family). Now that Klal Yisrael was founded, one should not go elsewhere to marry. Any sparks of Kedushah among the nations will come to Yisrael to convert.
I.e. one turned out righteous, and one wicked.
This approach is reminiscent of genetics, but in the spiritual sense. Rivkah was the parent of both a Tzadik and a Rasha (Tr), just as Lavan's children were mixed (Tr) (i.e. the daughters were righteous, but the sons later born were not. Or perhaps, Besu'el himself had fathered Rivkah but also Lavan (Tr)). The union of the Tzadik in each family had the likelihood to create pure Tzadikim (Tr x Tr = TT). (CS)
Yitzchak told Yaakov to go "Beisah Besu'el" (28:2). Why did he go to Lavan?
Malbim: Yitzchak thought that [Besu'el] 1 would guide him with his counsel. Yaakov feared Esav, and went to Lavan, who was powerful in the land, and would protect him.