If you need one, get one. If you can wait, wait. If you are thinking laptop, be prepared to wait 2 years as you'll be better off getting a rev b model.
You can't use an iPod with Macs and a PC. Has to be one or the other. Decide which and use the software update/reinstaller from apple.com and reformat.
You can do a search for the songs, Apple F, and see if they show up anywhere. Or have iTunes import any songs from your hard drive.
That said, you should always have a backup in mind. I have about 45GB of music and I bit the bullet once and made copies to an external hard drive as well as...
.Mac is well worth it, if used correctly. All the others offering, at intervals, web storage and email and what not are pale competitors. SpyMac, GMail, Yahoo360, MSN Plus, this site, etc.