Well... would you use the Mail, Stocks, Weather, Notes, or Web apps?
To be clear, most iPhone/iPod Touch-targeted Web apps will run just fine in Safari Mobile which is already included in the iPod Touch without needing to purchase the upgrade. Mail, Stocks, Weather, and Maps... those would require the upgrade.
Also, the risks of jailbreaking your iPod Touch are being slightly misrepresented... It is very rare that a jailbreak would actually "brick" the iPod Touch. Unless you do something silly like, say, delete the root filesystem, the odds are very good that you could always use the Restore feature in iTunes to bring a jailbroken iPod Touch back to its factory initial state, leaving no trace of the fact that it had even been jailbroken in the first place. (Unlike the SIM unlock process in an iPhone, which many people erroneously consider to be synonymous to the jailbreak process, there is no need to make any modifications to the bootloader or any other permanent changes in hardware or software to do the jailbreak.)
However, as the jailbreak is a violation of the software's EULA, you shouldn't expect to get very willing support from Apple in the event that you try to get warranty service without having first fully erased any traces of having previously performed the jailbreak.
As well, the jailbreak is very likely a violation of the DMCA, so if you live in the USA (or other jurisdictions which have similar laws) then you may want to consider the potential punishment you may face if Apple ever decided to actively pursue such cases of infringement.
