A good free app for iPod touch is the Calorie Tracker. Others however include Bloomberg, Free Translator and eReader. You can visit the iphonetouch.blorge.com/2009/03/22/top-40-best-free-ipod-touch-apps/ website for more apps.
If it has voice rec, dragon go is cool. Ask has an app as well. Google translator is good, imdb has an app. Fango is great as well as redbox. Of course Facebook has an app. Netflix has one as well. Hope this helps. God bless