I have just visited Nav Flight Services in PRG (mentioned above) and find their system very good and reasonably priced. SITA and Jeppesen I find very "user unfriendly" and expensive. Also visited Navtech, similar results but simpler graphics and can be hosted on your own servers. Today I visit Air Data so any questions on these systems just PM me and I will try to answer. Generally the smaller companies will tailor their systems to meet your requirements and savings can be as much as 50%.