Yes, the decision was made. My bank made an update of its Internet Banking, which resulted in incompatibility with Mac OS X. As it was almost the only bank to support Mac OS X over here, I am really sad.
Asking the technical support, they promised me to solve this issue within several weeks from now; I have decided to install Microsoft Windows XP on my Mac. As I have a very old notebook, I have the original license of Windows XP, which I can freely use as I will install the operating system just on one computer and I do not need the “Aqua-like†user interface of Windows Vista.
Currently, I know, I will not install Windows Vista using BootCamp Manager as I want to run Windows inside Mac OS X as I need them just for Internet banking, no other applications or games will be run from Windows.
So, should I use Parallel Desktop or VMWare? What is your recommendation?

VMWare
My vote is with VMware and their product, VMware Fusion (currently still in beta). Their broad experience with virtualization across many platforms (Windows, Linux, OS X, and bare metal) and their maturity weigh more heavily for me than Parallels’ Coherence feature (which is really the ONLY advantage they have).
Good luck!