Yes, the Blizzard1230 will get you up and running with OS3.9. Make sure that you'll be satisfied with an 030, however, as you'll save some money by going stright to an 060 accelerator rather than upgrading later.
An 030 on a plain AGA machine will just barely suffice for web surfing. The CPU time needed to decode and display images on the web will make it a rather slow experience.
As for antivirus and firewall, there's not much to worry about. The Amiga is great for "security though obscurity". No modern virii can affect the Amiga, and in the event you somehow get snagged with an old Amiga virus, any program that uses xvs.library will get you fixed up.