As we replacing our existing WEP infrastructure across multiple offices, we are weighing the value of upgrading to WPA versus WPA2 (both PSK). We have several different types of devices that do not support WPA2, so moving to that protocol has additional costs involved.
What I would like to know is what are the threats to WPA-PSK wireless networks? With that information, we will be able to balance the upgrade costs versus security threats.
Best Answer
WPA is "pretty secure", while WPA2 is "very secure". There are partial attacks against WPA in the wild already, and more complete attacks are expected to appear over time. WPA2 (using AES rather than TKIP) has no known vulnerabilities yet.
As you said, the decision as to which you choose is mostly up to the value of your data, but my personal suggestion is to migration to WPA2 now, rather than having to do it when a practical attack is discovered sometime in the next few years. Putting your wireless on a segregated subnet and treating it almost like "the internet" in terms of what access is allowed is also a good idea, given how easy it is to sniff.
Nice summary page: http://imps.mcmaster.ca/courses/SE-4C03-07/wiki/bournejc/wireless_security.html#2
EDIT: actually, the aircrack-ng team don't think WPA will be cracked anytime soon.