With all the features (aside from the hey, I am made by Apple price tag) of the iPod Touch, it is definitly a "wicked cool" gadget with unlimted potential.
So, how can you fill it up with apps for $0.00? Well, one great site you need to bookmark on Safari is www.freeappaday.com. Each day, there is a new iPod Touch/iPhone free app. So do the math: In a week you have 7 new free apps, 30 in a month, etc. These are not your typlical free apps. Any other day, they go for between $.99 to $3.99. They sponsor these apps for you to download.
That being said, there are 10 apps that I can not live without. In no particular order, they are: