What made Lavan come running to the well to greet Eliezer?
Rashi: When he saw the golden ornaments that Eliezer had placed on his sister, he realized that their guest was a wealthy man, so he went running out to him to see what was in it for him. 1
Seforno: He went to see the rich man who had come to town - not to invite him, just to look. 2
Why does it say "va'Yaratz Lavan El ha'Ish", and in verse 30 "va'Yavo El ha'Ish"?
Moshav Zekenim: At first he ran, frantic about money when he heard that a rich man came, in order to steal it. When he saw that Eliezer gave to his sister a ring and bracelets, and heard that he came regarding Nisu'in, then he came to him gently, honorably.
Ohr ha'Chayim: Refer to 23:29:152:1.
Rashi writes that when he saw the golden ornaments on Rivkah, Lavan ran to Eliezer. It says that he ran before he saw the ornaments!
Ohr ha'Chayim: When Lavan heard that a man was too friendly with his sister, he ran to confront him, amidst zealousness for [the sanctity of] his sister. When he saw the ornaments and heard Eliezer's intent, his anger subsided and he went to offer to host him, with gratitude.
Malbim: The next verse (when he saw the ornaments) explains this (why he ran).
Ha'Emek Davar: Once he heard Rivkah say that he blessed for coming to Beis Achei Adoni, he knew that he was from Avraham's house, so he went to greet him. He called him Baruch Hashem only after seeing the ornaments (and understanding that he was wealthy), and offered to host him only after hearing that Eliezer asked about this.
Why does it say "u'Shmo Lavan"? Bamidbar Rabah 10:5 says that this is for Tzadikim, but Resha'im, it says the name first, e.g. "Naval Shmo"!
R. Yitzchak (in Bamidbar Rabah): He was exceedingly white. 1
R. Berachiyah (in Bamidbar Rabah): He was Meluvan (perfect) in evil. 2
Ohr ha'Chayim: He went to the well with virtuous intent (refer to 23:29:152:1). Hashem does not deny the reward due to anyone, so the verse puts his name last, like a Tzadik.
רש"י: למה וירץ...אמר עשיר הוא זה, ונתן עיניו בממון: מנין לרש"י שלכן הוא רץ?
גור אריה: קשה שסדר הפסוקים הפוך- תחילה כתוב שרץ ואח"כ כתוב שראה את הנזם והצמידים? אלא שהפסוק בא לפרש שהוא רץ מפני שראה את הנזם והצמידים.
גור אריה: רש"י התקשה למה רשע זה רץ להכניס את אליעזר לביתו? אלא שהוא ראה את הנזם והצמידים.