Backup your Music folder BEFORE trying anything! If you fail to do so, don't write back here complaining that you just lost your music.....
Try this:
Hold the option key while opening iTunes. It will ask to go to a library or create a new one. Click on the choose a library. It should pop a sheet down. Go to in that window: Homefolder/music/iTunes/library old (or a previous library). Select Library old or a previous library (if there) and then click on choose. Some of your playlists won't be there but you can now play some music and see if the crashing goes away. If it does then its probably a corrupt library. I'm thinking that something in your iTunes folder is corrupt. If it still does it. Repeat the steps but select your current iTunes library to go back to your most recent library.