OpenOffice.org for text, spreadsheet, database, presentation, and database processing. There is really no need to spend money on office suite like MS Office.
Forget iChat, get Adium—all-in-one messenger.
Czech Republic holidays for Mac OS X iCal, including Easter days!
If you have problems using your Smart Card on older systems (does not happen with Snow Leopard anymore) with Parallels Desktop or VirtualBox because of device being busy you should kill pcscd process:
sudo kill pid_of_pcscd
To fix this permanently disable pcscd process:
sudo chmod -x /usr/bin/pcscd
Mac OS X updates will reset permissions so you may have to repeat this process after updates.