If you're looking for protection against the sort of folks who are looking for passwords and/or credit card numbers from anyone they can find, they'll almost certainly move on to an easier target rather than waste time cracking even mediocre crypto to get your credit info.
If you're worried about professionals targeting you in particular, then using a PC with any active wireless connection, or for that matter just using a PC in a public space is a bad idea. Between wireless sniffing, active attacks against wireless devices, "shoulder surfing" either directly or with binoculars, cameras with zoom, etc, if you are a specific target its not a good idea.
For that matter, just a smash and grab of your PC should be a bigger worry than the strength of your network link crypto. There were a number of incidents this spring of notebook PC theft from Starbucks users in San Francisco, and they were all basically just quick "bash and grab" direct attacks.
I'm not saying don't worry about crypto strength, I take that seriously too, but focus on the weakest links in the chain before getting too freaked out about the strength of your crypto.
Bob
Originally Posted by Doppy
It's better than cleartext against amateurs, but using encryption draws extra attention to you, so in terms of privacy and security it might end up making things worse by singling you out for targetting, but not actually providing good security against attack.