Gemara

(Mishnah): It is the nature of all four Avos to damage... If they damaged, the damager must pay from Meitav (highest quality land).

7a (Abaye) Contradiction: "From the best of his field and vineyard he will pay" teaches that only Idis may be paid. A Beraisa learns from "he will return" that Shavah Kesef (something worth money) may be given, even bran!

Answer (Rav Papa): All Metaltelim are considered Meitav. If they can't be sold here, they can be sold elsewhere. Land cannot be sold elsewhere. Therefore, one who pays with land must give Idis, so it will be easy to sell.

9a (Rav Huna): Damages are paid with money or Idis.

14b (Beraisa): 'Shavah Kesef' (in the Mishnah) teaches that Beis Din collects only if the damager has land. If the victim seized Metaltelim, Beis Din collects the damages from them.

Question: How does 'Shavah Kesef' connote only if the damager has land?

Answer (Rav Ashi): It is Shavah Kesef, but not money itself. Everything except land is considered money, for it can be taken elsewhere and sold.

Question (Rav Yehudah bar Chinena - Beraisa): "He will return" includes anything worth money, even bran (even if the damager has no land)!

Answer (Rav Huna brei d'Rav Yehoshua): We collect from orphans only if they inherited land. (From the damager himself, we collect from anything.)

Rishonim

Rif (2a): Meitav must be given when paying land. All Metaltelim are considered Meitav. If they can't be sold here, they can be sold elsewhere.

Nimukei Yosef (Bava Basra 46b): The Gemara connotes that if the seller has no money, he cannot tell the buyer to keep the item. Rather, he pays Metaltelim. If he has money, he pays it. He is like a borrower. Many permit a damager to give land, even if he has money. The Rambam disagrees.

Rosh (1:5): Rashi explains that Rav Huna teaches that if one has land or money, he may not pay with Metaltelim. Also the Rif says that Rav Papa argues with Rav Huna. R. Tam rules like Rav Huna. If he has money or Meitav, he pays with it. If not, all Metaltelim are Meitav. We must say that R. Tam holds that Rav Papa does not argue. If not, he would rule like him, for he is Basra. Rav Papa merely came to answer the contradiction. He does not deviate from the simple understanding of the verses, which discuss paying with Meitav or money. Alternatively, Rav Papa argues. Since Rav Ashi put Rav Huna's answer last, even though Rav Huna preceded Rav Papa, this shows that the Halachah follows Rav Huna. The Rif's opinion is primary. Rav Kahana was a Talmid of Rava; he is Basra, and he holds like Rav Papa. If he held like Rav Huna, the verse must teach that he can pay with the carcass even if he has money! The primary text of Rav Huna says 'money or Meitav.' He explains that the Mishnah requires Meitav, but money is like Meitav.

Rambam (Hilchos Nizkei Mamon 8:9): Beis Din first collects for the victim from the damager's Metaltelim. If this does not suffice, the rest is collected from his best land. As long as Metaltelim are found, even bran, we do not take land.

(Gra CM 419:1): He holds that Rav Huna teaches that the damager may give what he wants; 'money' includes Metaltelim. He and Rav Papa do not argue.

Rosh (ibid.): Regarding a borrower, if he has Metaltelim and land, we force him to give Metaltelim if the creditor wants it. Since he gave money, he collects whatever is closest to money, i.e. Metaltelim. The can be sold anywhere.

Poskim

Shulchan Aruch (419:1): Beis Din first collects Metaltelim for a victim of damage. As long as Metaltelim are found, even bran, we do not take land.

Beis Yosef (CM 389 DH keshe'Ba'in): The Rosh said that if the borrower has Metaltelim and land, the creditor can demand Metaltelim, since he gave money. The Tur understands that the same applies to damages. Even though the reason does not apply to damages, Chachamim did not distinguish.

Rebuttal #1 (SMA 1, Prishah DH Ro'in and Drishah 1): A lender has the upper hand. If a borrower has money or Metaltelim, he may not pay land, even if it is Idis. He should get back money, like he lent, or at least Metaltelim, which are like money. They can be sold anywhere. However, a damager has the upper hand. He may opt to pay Meitav or Metaltelim. This was Rav Papa's answer. He may pay Metaltelim, for they are Meitav. He may pay bran even if he has money. The Rosh (1:2) says that it is the damager's choice, as long as he does not give the victim less than he is entitled to. The Beis Yosef and Ir Shushan say that if the victim wants Metaltelim, the damager must give them. This is unlike the Tur.

Rebuttal #2 (Bach 1): The Magid Mishneh (Hilchos Nizkei Mamon 8:10 and Chovel u'Mazik 1:1) says that the damager chooses which he pays with.

Rebuttal #3 (Gra 1): The Rambam learns from a borrower. A borrower is different! If he has money, he must return money. Compared to land, Metaltelim are like money. Even Rav Huna, who is stringent, allows paying damages with money or Meitav. We hold like Rav Papa (who allows paying with bran). All the more so, one may pay with what he wants! The Rosh says 'and regarding a borrower...', which implies that it is different. Also, a borrower must pay money, like he received. The Shulchan Aruch rules like the Ramah; if he has money, he may not give Metaltelim or land; if he has Metaltelim, he may not give land. The Rambam holds that Rav Huna includes Metaltelim in 'money', and teaches that the damager may give what he wants. He and Rav Papa do not argue.

Defense (Shach 2): The Rambam says that we collect Metaltelim, without saying that it does not depend on the desire of the victim or damager. The Rambam and Tur say that if a damager died and left land and Metaltelim, we collect from the land. If a damager prefers to give Metaltelim, we should say so on behalf of the orphans! They should be no worse than the damager! The Rosh and Mordechai say that R. Tam connotes that the damager chooses what he wants to give, but the Rambam, Sefer ha'Terumos, R. Chananel, Ra'avan and Nimukei Yosef citing the Ramah disagree. When explaining R. Tam, the Rosh connotes that only a creditor can demand Metaltelim. The Rosh concludes like the Rif, who did not say that a damager can choose. The Rif allows him to give bran in place of money. This shows that the primary collection is with Metaltelim. Surely, a damager cannot choose to give land. It is unreasonable to say (like Rashi) that the Gemara (14b) thought that we collect only from one with land. Can one without land damage at will, and be exempt?! Rather, we collect Shavah Kesef against the damager's will. The Gemara thought that Shavah Kesef refers to land, but concludes that it is Metaltelim. A creditor can demand Metaltelim. A victim has better collection power, except for money (a damager may pay Metaltelim instead), for it says "Yashiv". There is no such source for a borrower; so he must return money, like he borrowed. There is no reason to distinguish creditors from borrowers regarding taking land in place of Metaltelim.