help for finding a suitable backup software

i am looking for a kind of software which can meet the following requirements:
1. It must suppot win 2008 server;
2. It should do schedule backup and incremental backup;
3. can suppot backup to network or other external hard drives
4. can have e-mail notification about the bakcup result;
5. stable and eays to use
I have a small company,so the cheaper the better. Of course, its quanlity should be good.
Thanks for everyone's help in advance.