Česká spořitelna is one of the the largest banks in Czech Republic. I am client of this bank for a long time and satisfied with their services. One of the services I am using is an internet-bank (Servis24).
It is web-based and works from Firefox without problem. Only issue for me was SMS confirmation for every transaction – i found that SMS delivery in roaming is not always reliable. Also i dislike password-based authentication. So I decided to order card for certificate.