Is PC-BSD secure enough for internet banking and how reliable is the current version of PC-BSD for everyday computing tasks?
I use PC-BSD 1.5.1 as my one and only OS at home.
It handles everything that I need it to do.
There are even graphics apps available that may allow you to get away from your "need" for an XP box.
I havent tried the latest version (7.1 Beta) yet.
I have tried 7.0. While it is good, KDE4 is just too rough around the edges for me to make the leap. PC-BSD 1.5.1 is great and very stable.
Your internet banking is probably through an SSL connection with the browser. The security is handled that way. The OS has little to do with it.
Konqueror and/or Firefox will have no problem handling it in PC-BSD.