In iTunes 10.0, most songs have a newly-added Ping drop-down button instead of the iTunes Store arrow links. Mac OS X Hints reader gid shares a Terminal command to keep that button from showing up:
First, quit iTunes if it's open. Then, start Terminal.app and enter: defaults write com.apple.iTunes hide-ping-dropdown 1. When iTunes is restarted, the Ping buttons should have disappeared. To reverse, just repeat, using 0 rather than 1.
If you'd like to get the old store arrows back, the old show-store-arrow-links hack no longer works. That setting has a new name and now defaults to Off (to allow for those Ping buttons). To restore the arrows (after you've removed the Ping drop-downs), enter this command in Terminal: defaults write com.apple.iTunes show-store-link-arrows 1. (Again, you can reverse that by entering the same command, but replacing the 1 with 0.
Finally, if you've restored the arrows, but you'd like them to point to your own library instead of to the iTunes Store (so when you click on the arrow next to a song title in a playlist, you'll go to that song's album in your iTunes library), you can use the invaluable invertStoreLinks setting: defaults write com.apple.iTunes invertStoreLinks 1. Once again, replace that 1 with 0 to reverse the command.
(It should be noted, as a few Hints commenters have, that some people think the Ping drop-down is actually more useful than the old store arrow; it gives you seven options, while the arrow is single-purpose.)
This story, "Get Rid of the Ping Drop-down" was originally published by Macworld.